1 # SPDX-License-Identifier: GPL-2.0-only 1 # SPDX-License-Identifier: GPL-2.0-only
2 # 2 #
3 # Architectures that offer an FUNCTION_TRACER 3 # Architectures that offer an FUNCTION_TRACER implementation should
4 # select HAVE_FUNCTION_TRACER: 4 # select HAVE_FUNCTION_TRACER:
5 # 5 #
6 6
7 config USER_STACKTRACE_SUPPORT 7 config USER_STACKTRACE_SUPPORT
8 bool 8 bool
9 9
10 config NOP_TRACER 10 config NOP_TRACER
11 bool 11 bool
12 12
13 config HAVE_RETHOOK <<
14 bool <<
15 <<
16 config RETHOOK <<
17 bool <<
18 depends on HAVE_RETHOOK <<
19 help <<
20 Enable generic return hooking featur <<
21 API, which will be used by other fun <<
22 features like fprobe and kprobes. <<
23 <<
24 config HAVE_FUNCTION_TRACER 13 config HAVE_FUNCTION_TRACER
25 bool 14 bool
26 help 15 help
27 See Documentation/trace/ftrace-desig 16 See Documentation/trace/ftrace-design.rst
28 17
29 config HAVE_FUNCTION_GRAPH_TRACER 18 config HAVE_FUNCTION_GRAPH_TRACER
30 bool 19 bool
31 help 20 help
32 See Documentation/trace/ftrace-desig 21 See Documentation/trace/ftrace-design.rst
33 22
34 config HAVE_FUNCTION_GRAPH_RETVAL <<
35 bool <<
36 <<
37 config HAVE_DYNAMIC_FTRACE 23 config HAVE_DYNAMIC_FTRACE
38 bool 24 bool
39 help 25 help
40 See Documentation/trace/ftrace-desig 26 See Documentation/trace/ftrace-design.rst
41 27
42 config HAVE_DYNAMIC_FTRACE_WITH_REGS 28 config HAVE_DYNAMIC_FTRACE_WITH_REGS
43 bool 29 bool
44 30
45 config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS 31 config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
46 bool 32 bool
47 33
48 config HAVE_DYNAMIC_FTRACE_WITH_CALL_OPS <<
49 bool <<
50 <<
51 config HAVE_DYNAMIC_FTRACE_WITH_ARGS 34 config HAVE_DYNAMIC_FTRACE_WITH_ARGS
52 bool 35 bool
53 help 36 help
54 If this is set, then arguments and st 37 If this is set, then arguments and stack can be found from
55 the ftrace_regs passed into the funct !! 38 the pt_regs passed into the function callback regs parameter
56 by default, even without setting the 39 by default, even without setting the REGS flag in the ftrace_ops.
57 This allows for use of ftrace_regs_ge !! 40 This allows for use of regs_get_kernel_argument() and
58 ftrace_regs_get_stack_pointer(). !! 41 kernel_stack_pointer().
59 <<
60 config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE <<
61 bool <<
62 help <<
63 If the architecture generates __patc <<
64 but does not want them included in t <<
65 42
66 config HAVE_FTRACE_MCOUNT_RECORD 43 config HAVE_FTRACE_MCOUNT_RECORD
67 bool 44 bool
68 help 45 help
69 See Documentation/trace/ftrace-desig 46 See Documentation/trace/ftrace-design.rst
70 47
71 config HAVE_SYSCALL_TRACEPOINTS 48 config HAVE_SYSCALL_TRACEPOINTS
72 bool 49 bool
73 help 50 help
74 See Documentation/trace/ftrace-desig 51 See Documentation/trace/ftrace-design.rst
75 52
76 config HAVE_FENTRY 53 config HAVE_FENTRY
77 bool 54 bool
78 help 55 help
79 Arch supports the gcc options -pg wi 56 Arch supports the gcc options -pg with -mfentry
80 57
81 config HAVE_NOP_MCOUNT 58 config HAVE_NOP_MCOUNT
82 bool 59 bool
83 help 60 help
84 Arch supports the gcc options -pg wi 61 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
85 62
86 config HAVE_OBJTOOL_MCOUNT 63 config HAVE_OBJTOOL_MCOUNT
87 bool 64 bool
88 help 65 help
89 Arch supports objtool --mcount 66 Arch supports objtool --mcount
90 67
91 config HAVE_OBJTOOL_NOP_MCOUNT <<
92 bool <<
93 help <<
94 Arch supports the objtool options -- <<
95 An architecture can select this if i <<
96 of ftrace locations. <<
97 <<
98 config HAVE_C_RECORDMCOUNT 68 config HAVE_C_RECORDMCOUNT
99 bool 69 bool
100 help 70 help
101 C version of recordmcount available? 71 C version of recordmcount available?
102 72
103 config HAVE_BUILDTIME_MCOUNT_SORT 73 config HAVE_BUILDTIME_MCOUNT_SORT
104 bool 74 bool
105 help 75 help
106 An architecture selects this if it so 76 An architecture selects this if it sorts the mcount_loc section
107 at build time. 77 at build time.
108 78
109 config BUILDTIME_MCOUNT_SORT 79 config BUILDTIME_MCOUNT_SORT
110 bool 80 bool
111 default y 81 default y
112 depends on HAVE_BUILDTIME_MCOUNT_SORT & 82 depends on HAVE_BUILDTIME_MCOUNT_SORT && DYNAMIC_FTRACE
113 help 83 help
114 Sort the mcount_loc section at build 84 Sort the mcount_loc section at build time.
115 85
116 config TRACER_MAX_TRACE 86 config TRACER_MAX_TRACE
117 bool 87 bool
118 88
119 config TRACE_CLOCK 89 config TRACE_CLOCK
120 bool 90 bool
121 91
122 config RING_BUFFER 92 config RING_BUFFER
123 bool 93 bool
124 select TRACE_CLOCK 94 select TRACE_CLOCK
125 select IRQ_WORK 95 select IRQ_WORK
126 96
127 config EVENT_TRACING 97 config EVENT_TRACING
128 select CONTEXT_SWITCH_TRACER 98 select CONTEXT_SWITCH_TRACER
129 select GLOB 99 select GLOB
130 bool 100 bool
131 101
132 config CONTEXT_SWITCH_TRACER 102 config CONTEXT_SWITCH_TRACER
133 bool 103 bool
134 104
135 config RING_BUFFER_ALLOW_SWAP 105 config RING_BUFFER_ALLOW_SWAP
136 bool 106 bool
137 help 107 help
138 Allow the use of ring_buffer_swap_cpu 108 Allow the use of ring_buffer_swap_cpu.
139 Adds a very slight overhead to tracin 109 Adds a very slight overhead to tracing when enabled.
140 110
141 config PREEMPTIRQ_TRACEPOINTS 111 config PREEMPTIRQ_TRACEPOINTS
142 bool 112 bool
143 depends on TRACE_PREEMPT_TOGGLE || TRA 113 depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
144 select TRACING 114 select TRACING
145 default y 115 default y
146 help 116 help
147 Create preempt/irq toggle tracepoint 117 Create preempt/irq toggle tracepoints if needed, so that other parts
148 of the kernel can use them to genera 118 of the kernel can use them to generate or add hooks to them.
149 119
150 # All tracer options should select GENERIC_TRA 120 # All tracer options should select GENERIC_TRACER. For those options that are
151 # enabled by all tracers (context switch and e 121 # enabled by all tracers (context switch and event tracer) they select TRACING.
152 # This allows those options to appear when no 122 # This allows those options to appear when no other tracer is selected. But the
153 # options do not appear when something else se 123 # options do not appear when something else selects it. We need the two options
154 # GENERIC_TRACER and TRACING to avoid circular 124 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
155 # hiding of the automatic options. 125 # hiding of the automatic options.
156 126
157 config TRACING 127 config TRACING
158 bool 128 bool
159 select RING_BUFFER 129 select RING_BUFFER
160 select STACKTRACE if STACKTRACE_SUPPOR 130 select STACKTRACE if STACKTRACE_SUPPORT
161 select TRACEPOINTS 131 select TRACEPOINTS
162 select NOP_TRACER 132 select NOP_TRACER
163 select BINARY_PRINTF 133 select BINARY_PRINTF
164 select EVENT_TRACING 134 select EVENT_TRACING
165 select TRACE_CLOCK 135 select TRACE_CLOCK
166 select NEED_TASKS_RCU <<
167 136
168 config GENERIC_TRACER 137 config GENERIC_TRACER
169 bool 138 bool
170 select TRACING 139 select TRACING
171 140
172 # 141 #
173 # Minimum requirements an architecture has to 142 # Minimum requirements an architecture has to meet for us to
174 # be able to offer generic tracing facilities: 143 # be able to offer generic tracing facilities:
175 # 144 #
176 config TRACING_SUPPORT 145 config TRACING_SUPPORT
177 bool 146 bool
178 depends on TRACE_IRQFLAGS_SUPPORT 147 depends on TRACE_IRQFLAGS_SUPPORT
179 depends on STACKTRACE_SUPPORT 148 depends on STACKTRACE_SUPPORT
180 default y 149 default y
181 150
182 menuconfig FTRACE 151 menuconfig FTRACE
183 bool "Tracers" 152 bool "Tracers"
184 depends on TRACING_SUPPORT 153 depends on TRACING_SUPPORT
185 default y if DEBUG_KERNEL 154 default y if DEBUG_KERNEL
186 help 155 help
187 Enable the kernel tracing infrastruc 156 Enable the kernel tracing infrastructure.
188 157
189 if FTRACE 158 if FTRACE
190 159
191 config BOOTTIME_TRACING 160 config BOOTTIME_TRACING
192 bool "Boot-time Tracing support" 161 bool "Boot-time Tracing support"
193 depends on TRACING 162 depends on TRACING
194 select BOOT_CONFIG 163 select BOOT_CONFIG
195 help 164 help
196 Enable developer to setup ftrace sub 165 Enable developer to setup ftrace subsystem via supplemental
197 kernel cmdline at boot time for debu 166 kernel cmdline at boot time for debugging (tracing) driver
198 initialization and boot process. 167 initialization and boot process.
199 168
200 config FUNCTION_TRACER 169 config FUNCTION_TRACER
201 bool "Kernel Function Tracer" 170 bool "Kernel Function Tracer"
202 depends on HAVE_FUNCTION_TRACER 171 depends on HAVE_FUNCTION_TRACER
203 select KALLSYMS 172 select KALLSYMS
204 select GENERIC_TRACER 173 select GENERIC_TRACER
205 select CONTEXT_SWITCH_TRACER 174 select CONTEXT_SWITCH_TRACER
206 select GLOB 175 select GLOB
207 select NEED_TASKS_RCU !! 176 select TASKS_RCU if PREEMPTION
208 select TASKS_RUDE_RCU 177 select TASKS_RUDE_RCU
209 help 178 help
210 Enable the kernel to trace every ker 179 Enable the kernel to trace every kernel function. This is done
211 by using a compiler feature to inser 180 by using a compiler feature to insert a small, 5-byte No-Operation
212 instruction at the beginning of ever 181 instruction at the beginning of every kernel function, which NOP
213 sequence is then dynamically patched 182 sequence is then dynamically patched into a tracer call when
214 tracing is enabled by the administra 183 tracing is enabled by the administrator. If it's runtime disabled
215 (the bootup default), then the overh 184 (the bootup default), then the overhead of the instructions is very
216 small and not measurable even in mic !! 185 small and not measurable even in micro-benchmarks.
217 x86, but may have impact on other ar <<
218 186
219 config FUNCTION_GRAPH_TRACER 187 config FUNCTION_GRAPH_TRACER
220 bool "Kernel Function Graph Tracer" 188 bool "Kernel Function Graph Tracer"
221 depends on HAVE_FUNCTION_GRAPH_TRACER 189 depends on HAVE_FUNCTION_GRAPH_TRACER
222 depends on FUNCTION_TRACER 190 depends on FUNCTION_TRACER
223 depends on !X86_32 || !CC_OPTIMIZE_FOR 191 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
224 default y 192 default y
225 help 193 help
226 Enable the kernel to trace a functio 194 Enable the kernel to trace a function at both its return
227 and its entry. 195 and its entry.
228 Its first purpose is to trace the du 196 Its first purpose is to trace the duration of functions and
229 draw a call graph for each thread wi 197 draw a call graph for each thread with some information like
230 the return value. This is done by se 198 the return value. This is done by setting the current return
231 address on the current task structur 199 address on the current task structure into a stack of calls.
232 200
233 config FUNCTION_GRAPH_RETVAL <<
234 bool "Kernel Function Graph Return Val <<
235 depends on HAVE_FUNCTION_GRAPH_RETVAL <<
236 depends on FUNCTION_GRAPH_TRACER <<
237 default n <<
238 help <<
239 Support recording and printing the f <<
240 using function graph tracer. It can <<
241 that return errors. This feature is <<
242 enable it via the trace option funcg <<
243 See Documentation/trace/ftrace.rst <<
244 <<
245 config DYNAMIC_FTRACE 201 config DYNAMIC_FTRACE
246 bool "enable/disable function tracing 202 bool "enable/disable function tracing dynamically"
247 depends on FUNCTION_TRACER 203 depends on FUNCTION_TRACER
248 depends on HAVE_DYNAMIC_FTRACE 204 depends on HAVE_DYNAMIC_FTRACE
249 default y 205 default y
250 help 206 help
251 This option will modify all the call 207 This option will modify all the calls to function tracing
252 dynamically (will patch them out of 208 dynamically (will patch them out of the binary image and
253 replace them with a No-Op instructio 209 replace them with a No-Op instruction) on boot up. During
254 compile time, a table is made of all 210 compile time, a table is made of all the locations that ftrace
255 can function trace, and this table i 211 can function trace, and this table is linked into the kernel
256 image. When this is enabled, functio 212 image. When this is enabled, functions can be individually
257 enabled, and the functions not enabl 213 enabled, and the functions not enabled will not affect
258 performance of the system. 214 performance of the system.
259 215
260 See the files in /sys/kernel/tracing !! 216 See the files in /sys/kernel/debug/tracing:
261 available_filter_functions 217 available_filter_functions
262 set_ftrace_filter 218 set_ftrace_filter
263 set_ftrace_notrace 219 set_ftrace_notrace
264 220
265 This way a CONFIG_FUNCTION_TRACER ke 221 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
266 otherwise has native performance as 222 otherwise has native performance as long as no tracing is active.
267 223
268 config DYNAMIC_FTRACE_WITH_REGS 224 config DYNAMIC_FTRACE_WITH_REGS
269 def_bool y 225 def_bool y
270 depends on DYNAMIC_FTRACE 226 depends on DYNAMIC_FTRACE
271 depends on HAVE_DYNAMIC_FTRACE_WITH_RE 227 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
272 228
273 config DYNAMIC_FTRACE_WITH_DIRECT_CALLS 229 config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
274 def_bool y 230 def_bool y
275 depends on DYNAMIC_FTRACE_WITH_REGS || !! 231 depends on DYNAMIC_FTRACE_WITH_REGS
276 depends on HAVE_DYNAMIC_FTRACE_WITH_DI 232 depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
277 233
278 config DYNAMIC_FTRACE_WITH_CALL_OPS <<
279 def_bool y <<
280 depends on HAVE_DYNAMIC_FTRACE_WITH_CA <<
281 <<
282 config DYNAMIC_FTRACE_WITH_ARGS 234 config DYNAMIC_FTRACE_WITH_ARGS
283 def_bool y 235 def_bool y
284 depends on DYNAMIC_FTRACE 236 depends on DYNAMIC_FTRACE
285 depends on HAVE_DYNAMIC_FTRACE_WITH_AR 237 depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
286 238
287 config FPROBE <<
288 bool "Kernel Function Probe (fprobe)" <<
289 depends on FUNCTION_TRACER <<
290 depends on DYNAMIC_FTRACE_WITH_REGS <<
291 depends on HAVE_RETHOOK <<
292 select RETHOOK <<
293 default n <<
294 help <<
295 This option enables kernel function <<
296 The fprobe is similar to kprobes, bu <<
297 entries and exits. This also can pro <<
298 fprobe. <<
299 <<
300 If unsure, say N. <<
301 <<
302 config FUNCTION_PROFILER 239 config FUNCTION_PROFILER
303 bool "Kernel function profiler" 240 bool "Kernel function profiler"
304 depends on FUNCTION_TRACER 241 depends on FUNCTION_TRACER
305 default n 242 default n
306 help 243 help
307 This option enables the kernel funct 244 This option enables the kernel function profiler. A file is created
308 in debugfs called function_profile_e 245 in debugfs called function_profile_enabled which defaults to zero.
309 When a 1 is echoed into this file pr 246 When a 1 is echoed into this file profiling begins, and when a
310 zero is entered, profiling stops. A 247 zero is entered, profiling stops. A "functions" file is created in
311 the trace_stat directory; this file 248 the trace_stat directory; this file shows the list of functions that
312 have been hit and their counters. 249 have been hit and their counters.
313 250
314 If in doubt, say N. 251 If in doubt, say N.
315 252
316 config STACK_TRACER 253 config STACK_TRACER
317 bool "Trace max stack" 254 bool "Trace max stack"
318 depends on HAVE_FUNCTION_TRACER 255 depends on HAVE_FUNCTION_TRACER
319 select FUNCTION_TRACER 256 select FUNCTION_TRACER
320 select STACKTRACE 257 select STACKTRACE
321 select KALLSYMS 258 select KALLSYMS
322 help 259 help
323 This special tracer records the maxi 260 This special tracer records the maximum stack footprint of the
324 kernel and displays it in /sys/kerne !! 261 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
325 262
326 This tracer works by hooking into ev 263 This tracer works by hooking into every function call that the
327 kernel executes, and keeping a maxim 264 kernel executes, and keeping a maximum stack depth value and
328 stack-trace saved. If this is confi 265 stack-trace saved. If this is configured with DYNAMIC_FTRACE
329 then it will not have any overhead w 266 then it will not have any overhead while the stack tracer
330 is disabled. 267 is disabled.
331 268
332 To enable the stack tracer on bootup 269 To enable the stack tracer on bootup, pass in 'stacktrace'
333 on the kernel command line. 270 on the kernel command line.
334 271
335 The stack tracer can also be enabled 272 The stack tracer can also be enabled or disabled via the
336 sysctl kernel.stack_tracer_enabled 273 sysctl kernel.stack_tracer_enabled
337 274
338 Say N if unsure. 275 Say N if unsure.
339 276
340 config TRACE_PREEMPT_TOGGLE 277 config TRACE_PREEMPT_TOGGLE
341 bool 278 bool
342 help 279 help
343 Enables hooks which will be called w 280 Enables hooks which will be called when preemption is first disabled,
344 and last enabled. 281 and last enabled.
345 282
346 config IRQSOFF_TRACER 283 config IRQSOFF_TRACER
347 bool "Interrupts-off Latency Tracer" 284 bool "Interrupts-off Latency Tracer"
348 default n 285 default n
349 depends on TRACE_IRQFLAGS_SUPPORT 286 depends on TRACE_IRQFLAGS_SUPPORT
350 select TRACE_IRQFLAGS 287 select TRACE_IRQFLAGS
351 select GENERIC_TRACER 288 select GENERIC_TRACER
352 select TRACER_MAX_TRACE 289 select TRACER_MAX_TRACE
353 select RING_BUFFER_ALLOW_SWAP 290 select RING_BUFFER_ALLOW_SWAP
354 select TRACER_SNAPSHOT 291 select TRACER_SNAPSHOT
355 select TRACER_SNAPSHOT_PER_CPU_SWAP 292 select TRACER_SNAPSHOT_PER_CPU_SWAP
356 help 293 help
357 This option measures the time spent 294 This option measures the time spent in irqs-off critical
358 sections, with microsecond accuracy. 295 sections, with microsecond accuracy.
359 296
360 The default measurement method is a 297 The default measurement method is a maximum search, which is
361 disabled by default and can be runti 298 disabled by default and can be runtime (re-)started
362 via: 299 via:
363 300
364 echo 0 > /sys/kernel/tracing/tra !! 301 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
365 302
366 (Note that kernel size and overhead 303 (Note that kernel size and overhead increase with this option
367 enabled. This option and the preempt 304 enabled. This option and the preempt-off timing option can be
368 used together or separately.) 305 used together or separately.)
369 306
370 config PREEMPT_TRACER 307 config PREEMPT_TRACER
371 bool "Preemption-off Latency Tracer" 308 bool "Preemption-off Latency Tracer"
372 default n 309 default n
373 depends on PREEMPTION 310 depends on PREEMPTION
374 select GENERIC_TRACER 311 select GENERIC_TRACER
375 select TRACER_MAX_TRACE 312 select TRACER_MAX_TRACE
376 select RING_BUFFER_ALLOW_SWAP 313 select RING_BUFFER_ALLOW_SWAP
377 select TRACER_SNAPSHOT 314 select TRACER_SNAPSHOT
378 select TRACER_SNAPSHOT_PER_CPU_SWAP 315 select TRACER_SNAPSHOT_PER_CPU_SWAP
379 select TRACE_PREEMPT_TOGGLE 316 select TRACE_PREEMPT_TOGGLE
380 help 317 help
381 This option measures the time spent 318 This option measures the time spent in preemption-off critical
382 sections, with microsecond accuracy. 319 sections, with microsecond accuracy.
383 320
384 The default measurement method is a 321 The default measurement method is a maximum search, which is
385 disabled by default and can be runti 322 disabled by default and can be runtime (re-)started
386 via: 323 via:
387 324
388 echo 0 > /sys/kernel/tracing/tra !! 325 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
389 326
390 (Note that kernel size and overhead 327 (Note that kernel size and overhead increase with this option
391 enabled. This option and the irqs-of 328 enabled. This option and the irqs-off timing option can be
392 used together or separately.) 329 used together or separately.)
393 330
394 config SCHED_TRACER 331 config SCHED_TRACER
395 bool "Scheduling Latency Tracer" 332 bool "Scheduling Latency Tracer"
396 select GENERIC_TRACER 333 select GENERIC_TRACER
397 select CONTEXT_SWITCH_TRACER 334 select CONTEXT_SWITCH_TRACER
398 select TRACER_MAX_TRACE 335 select TRACER_MAX_TRACE
399 select TRACER_SNAPSHOT 336 select TRACER_SNAPSHOT
400 help 337 help
401 This tracer tracks the latency of th 338 This tracer tracks the latency of the highest priority task
402 to be scheduled in, starting from th 339 to be scheduled in, starting from the point it has woken up.
403 340
404 config HWLAT_TRACER 341 config HWLAT_TRACER
405 bool "Tracer to detect hardware latenc 342 bool "Tracer to detect hardware latencies (like SMIs)"
406 select GENERIC_TRACER 343 select GENERIC_TRACER
407 select TRACER_MAX_TRACE <<
408 help 344 help
409 This tracer, when enabled will create 345 This tracer, when enabled will create one or more kernel threads,
410 depending on what the cpumask file is 346 depending on what the cpumask file is set to, which each thread
411 spinning in a loop looking for interr 347 spinning in a loop looking for interruptions caused by
412 something other than the kernel. For 348 something other than the kernel. For example, if a
413 System Management Interrupt (SMI) tak 349 System Management Interrupt (SMI) takes a noticeable amount of
414 time, this tracer will detect it. Thi 350 time, this tracer will detect it. This is useful for testing
415 if a system is reliable for Real Time 351 if a system is reliable for Real Time tasks.
416 352
417 Some files are created in the tracing 353 Some files are created in the tracing directory when this
418 is enabled: 354 is enabled:
419 355
420 hwlat_detector/width - time in us 356 hwlat_detector/width - time in usecs for how long to spin for
421 hwlat_detector/window - time in us 357 hwlat_detector/window - time in usecs between the start of each
422 iteration 358 iteration
423 359
424 A kernel thread is created that will 360 A kernel thread is created that will spin with interrupts disabled
425 for "width" microseconds in every "wi 361 for "width" microseconds in every "window" cycle. It will not spin
426 for "window - width" microseconds, wh 362 for "window - width" microseconds, where the system can
427 continue to operate. 363 continue to operate.
428 364
429 The output will appear in the trace a 365 The output will appear in the trace and trace_pipe files.
430 366
431 When the tracer is not running, it ha 367 When the tracer is not running, it has no affect on the system,
432 but when it is running, it can cause 368 but when it is running, it can cause the system to be
433 periodically non responsive. Do not r 369 periodically non responsive. Do not run this tracer on a
434 production system. 370 production system.
435 371
436 To enable this tracer, echo in "hwlat 372 To enable this tracer, echo in "hwlat" into the current_tracer
437 file. Every time a latency is greater 373 file. Every time a latency is greater than tracing_thresh, it will
438 be recorded into the ring buffer. 374 be recorded into the ring buffer.
439 375
440 config OSNOISE_TRACER 376 config OSNOISE_TRACER
441 bool "OS Noise tracer" 377 bool "OS Noise tracer"
442 select GENERIC_TRACER 378 select GENERIC_TRACER
443 select TRACER_MAX_TRACE <<
444 help 379 help
445 In the context of high-performance c 380 In the context of high-performance computing (HPC), the Operating
446 System Noise (osnoise) refers to the 381 System Noise (osnoise) refers to the interference experienced by an
447 application due to activities inside 382 application due to activities inside the operating system. In the
448 context of Linux, NMIs, IRQs, SoftIR 383 context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
449 can cause noise to the system. Moreo 384 can cause noise to the system. Moreover, hardware-related jobs can
450 also cause noise, for example, via S 385 also cause noise, for example, via SMIs.
451 386
452 The osnoise tracer leverages the hwl 387 The osnoise tracer leverages the hwlat_detector by running a similar
453 loop with preemption, SoftIRQs and I 388 loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
454 the sources of osnoise during its ex 389 the sources of osnoise during its execution. The osnoise tracer takes
455 note of the entry and exit point of 390 note of the entry and exit point of any source of interferences,
456 increasing a per-cpu interference co 391 increasing a per-cpu interference counter. It saves an interference
457 counter for each source of interfere 392 counter for each source of interference. The interference counter for
458 NMI, IRQs, SoftIRQs, and threads is 393 NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
459 observes these interferences' entry 394 observes these interferences' entry events. When a noise happens
460 without any interference from the op 395 without any interference from the operating system level, the
461 hardware noise counter increases, po 396 hardware noise counter increases, pointing to a hardware-related
462 noise. In this way, osnoise can acco 397 noise. In this way, osnoise can account for any source of
463 interference. At the end of the peri 398 interference. At the end of the period, the osnoise tracer prints
464 the sum of all noise, the max single 399 the sum of all noise, the max single noise, the percentage of CPU
465 available for the thread, and the co 400 available for the thread, and the counters for the noise sources.
466 401
467 In addition to the tracer, a set of 402 In addition to the tracer, a set of tracepoints were added to
468 facilitate the identification of the 403 facilitate the identification of the osnoise source.
469 404
470 The output will appear in the trace 405 The output will appear in the trace and trace_pipe files.
471 406
472 To enable this tracer, echo in "osno 407 To enable this tracer, echo in "osnoise" into the current_tracer
473 file. 408 file.
474 409
475 config TIMERLAT_TRACER 410 config TIMERLAT_TRACER
476 bool "Timerlat tracer" 411 bool "Timerlat tracer"
477 select OSNOISE_TRACER 412 select OSNOISE_TRACER
478 select GENERIC_TRACER 413 select GENERIC_TRACER
479 help 414 help
480 The timerlat tracer aims to help the 415 The timerlat tracer aims to help the preemptive kernel developers
481 to find sources of wakeup latencies 416 to find sources of wakeup latencies of real-time threads.
482 417
483 The tracer creates a per-cpu kernel 418 The tracer creates a per-cpu kernel thread with real-time priority.
484 The tracer thread sets a periodic ti 419 The tracer thread sets a periodic timer to wakeup itself, and goes
485 to sleep waiting for the timer to fi 420 to sleep waiting for the timer to fire. At the wakeup, the thread
486 then computes a wakeup latency value 421 then computes a wakeup latency value as the difference between
487 the current time and the absolute ti 422 the current time and the absolute time that the timer was set
488 to expire. 423 to expire.
489 424
490 The tracer prints two lines at every 425 The tracer prints two lines at every activation. The first is the
491 timer latency observed at the hardir 426 timer latency observed at the hardirq context before the
492 activation of the thread. The second 427 activation of the thread. The second is the timer latency observed
493 by the thread, which is the same lev 428 by the thread, which is the same level that cyclictest reports. The
494 ACTIVATION ID field serves to relate 429 ACTIVATION ID field serves to relate the irq execution to its
495 respective thread execution. 430 respective thread execution.
496 431
497 The tracer is build on top of osnois 432 The tracer is build on top of osnoise tracer, and the osnoise:
498 events can be used to trace the sour 433 events can be used to trace the source of interference from NMI,
499 IRQs and other threads. It also enab 434 IRQs and other threads. It also enables the capture of the
500 stacktrace at the IRQ context, which 435 stacktrace at the IRQ context, which helps to identify the code
501 path that can cause thread delay. 436 path that can cause thread delay.
502 437
503 config MMIOTRACE 438 config MMIOTRACE
504 bool "Memory mapped IO tracing" 439 bool "Memory mapped IO tracing"
505 depends on HAVE_MMIOTRACE_SUPPORT && P 440 depends on HAVE_MMIOTRACE_SUPPORT && PCI
506 select GENERIC_TRACER 441 select GENERIC_TRACER
507 help 442 help
508 Mmiotrace traces Memory Mapped I/O a 443 Mmiotrace traces Memory Mapped I/O access and is meant for
509 debugging and reverse engineering. I 444 debugging and reverse engineering. It is called from the ioremap
510 implementation and works via page fa 445 implementation and works via page faults. Tracing is disabled by
511 default and can be enabled at run-ti 446 default and can be enabled at run-time.
512 447
513 See Documentation/trace/mmiotrace.rs 448 See Documentation/trace/mmiotrace.rst.
514 If you are not helping to develop dr 449 If you are not helping to develop drivers, say N.
515 450
516 config ENABLE_DEFAULT_TRACERS 451 config ENABLE_DEFAULT_TRACERS
517 bool "Trace process context switches a 452 bool "Trace process context switches and events"
518 depends on !GENERIC_TRACER 453 depends on !GENERIC_TRACER
519 select TRACING 454 select TRACING
520 help 455 help
521 This tracer hooks to various trace p 456 This tracer hooks to various trace points in the kernel,
522 allowing the user to pick and choose 457 allowing the user to pick and choose which trace point they
523 want to trace. It also includes the 458 want to trace. It also includes the sched_switch tracer plugin.
524 459
525 config FTRACE_SYSCALLS 460 config FTRACE_SYSCALLS
526 bool "Trace syscalls" 461 bool "Trace syscalls"
527 depends on HAVE_SYSCALL_TRACEPOINTS 462 depends on HAVE_SYSCALL_TRACEPOINTS
528 select GENERIC_TRACER 463 select GENERIC_TRACER
529 select KALLSYMS 464 select KALLSYMS
530 help 465 help
531 Basic tracer to catch the syscall en 466 Basic tracer to catch the syscall entry and exit events.
532 467
533 config TRACER_SNAPSHOT 468 config TRACER_SNAPSHOT
534 bool "Create a snapshot trace buffer" 469 bool "Create a snapshot trace buffer"
535 select TRACER_MAX_TRACE 470 select TRACER_MAX_TRACE
536 help 471 help
537 Allow tracing users to take snapshot 472 Allow tracing users to take snapshot of the current buffer using the
538 ftrace interface, e.g.: 473 ftrace interface, e.g.:
539 474
540 echo 1 > /sys/kernel/tracing/sna !! 475 echo 1 > /sys/kernel/debug/tracing/snapshot
541 cat snapshot 476 cat snapshot
542 477
543 config TRACER_SNAPSHOT_PER_CPU_SWAP 478 config TRACER_SNAPSHOT_PER_CPU_SWAP
544 bool "Allow snapshot to swap per CPU" 479 bool "Allow snapshot to swap per CPU"
545 depends on TRACER_SNAPSHOT 480 depends on TRACER_SNAPSHOT
546 select RING_BUFFER_ALLOW_SWAP 481 select RING_BUFFER_ALLOW_SWAP
547 help 482 help
548 Allow doing a snapshot of a single C 483 Allow doing a snapshot of a single CPU buffer instead of a
549 full swap (all buffers). If this is 484 full swap (all buffers). If this is set, then the following is
550 allowed: 485 allowed:
551 486
552 echo 1 > /sys/kernel/tracing/per !! 487 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
553 488
554 After which, only the tracing buffer 489 After which, only the tracing buffer for CPU 2 was swapped with
555 the main tracing buffer, and the oth 490 the main tracing buffer, and the other CPU buffers remain the same.
556 491
557 When this is enabled, this adds a li 492 When this is enabled, this adds a little more overhead to the
558 trace recording, as it needs to add 493 trace recording, as it needs to add some checks to synchronize
559 recording with swaps. But this does 494 recording with swaps. But this does not affect the performance
560 of the overall system. This is enabl 495 of the overall system. This is enabled by default when the preempt
561 or irq latency tracers are enabled, 496 or irq latency tracers are enabled, as those need to swap as well
562 and already adds the overhead (plus 497 and already adds the overhead (plus a lot more).
563 498
564 config TRACE_BRANCH_PROFILING 499 config TRACE_BRANCH_PROFILING
565 bool 500 bool
566 select GENERIC_TRACER 501 select GENERIC_TRACER
567 502
568 choice 503 choice
569 prompt "Branch Profiling" 504 prompt "Branch Profiling"
570 default BRANCH_PROFILE_NONE 505 default BRANCH_PROFILE_NONE
571 help 506 help
572 The branch profiling is a software pr 507 The branch profiling is a software profiler. It will add hooks
573 into the C conditionals to test which 508 into the C conditionals to test which path a branch takes.
574 509
575 The likely/unlikely profiler only loo 510 The likely/unlikely profiler only looks at the conditions that
576 are annotated with a likely or unlike 511 are annotated with a likely or unlikely macro.
577 512
578 The "all branch" profiler will profil 513 The "all branch" profiler will profile every if-statement in the
579 kernel. This profiler will also enabl 514 kernel. This profiler will also enable the likely/unlikely
580 profiler. 515 profiler.
581 516
582 Either of the above profilers adds a 517 Either of the above profilers adds a bit of overhead to the system.
583 If unsure, choose "No branch profilin 518 If unsure, choose "No branch profiling".
584 519
585 config BRANCH_PROFILE_NONE 520 config BRANCH_PROFILE_NONE
586 bool "No branch profiling" 521 bool "No branch profiling"
587 help 522 help
588 No branch profiling. Branch profilin 523 No branch profiling. Branch profiling adds a bit of overhead.
589 Only enable it if you want to analys 524 Only enable it if you want to analyse the branching behavior.
590 Otherwise keep it disabled. 525 Otherwise keep it disabled.
591 526
592 config PROFILE_ANNOTATED_BRANCHES 527 config PROFILE_ANNOTATED_BRANCHES
593 bool "Trace likely/unlikely profiler" 528 bool "Trace likely/unlikely profiler"
594 select TRACE_BRANCH_PROFILING 529 select TRACE_BRANCH_PROFILING
595 help 530 help
596 This tracer profiles all likely and 531 This tracer profiles all likely and unlikely macros
597 in the kernel. It will display the r 532 in the kernel. It will display the results in:
598 533
599 /sys/kernel/tracing/trace_stat/branc !! 534 /sys/kernel/debug/tracing/trace_stat/branch_annotated
600 535
601 Note: this will add a significant ov 536 Note: this will add a significant overhead; only turn this
602 on if you need to profile the system 537 on if you need to profile the system's use of these macros.
603 538
604 config PROFILE_ALL_BRANCHES 539 config PROFILE_ALL_BRANCHES
605 bool "Profile all if conditionals" if 540 bool "Profile all if conditionals" if !FORTIFY_SOURCE
606 select TRACE_BRANCH_PROFILING 541 select TRACE_BRANCH_PROFILING
607 help 542 help
608 This tracer profiles all branch cond 543 This tracer profiles all branch conditions. Every if ()
609 taken in the kernel is recorded whet 544 taken in the kernel is recorded whether it hit or miss.
610 The results will be displayed in: 545 The results will be displayed in:
611 546
612 /sys/kernel/tracing/trace_stat/branc !! 547 /sys/kernel/debug/tracing/trace_stat/branch_all
613 548
614 This option also enables the likely/ 549 This option also enables the likely/unlikely profiler.
615 550
616 This configuration, when enabled, wi 551 This configuration, when enabled, will impose a great overhead
617 on the system. This should only be e 552 on the system. This should only be enabled when the system
618 is to be analyzed in much detail. 553 is to be analyzed in much detail.
619 endchoice 554 endchoice
620 555
621 config TRACING_BRANCHES 556 config TRACING_BRANCHES
622 bool 557 bool
623 help 558 help
624 Selected by tracers that will trace 559 Selected by tracers that will trace the likely and unlikely
625 conditions. This prevents the tracer 560 conditions. This prevents the tracers themselves from being
626 profiled. Profiling the tracing infr 561 profiled. Profiling the tracing infrastructure can only happen
627 when the likelys and unlikelys are n 562 when the likelys and unlikelys are not being traced.
628 563
629 config BRANCH_TRACER 564 config BRANCH_TRACER
630 bool "Trace likely/unlikely instances" 565 bool "Trace likely/unlikely instances"
631 depends on TRACE_BRANCH_PROFILING 566 depends on TRACE_BRANCH_PROFILING
632 select TRACING_BRANCHES 567 select TRACING_BRANCHES
633 help 568 help
634 This traces the events of likely and 569 This traces the events of likely and unlikely condition
635 calls in the kernel. The difference 570 calls in the kernel. The difference between this and the
636 "Trace likely/unlikely profiler" is 571 "Trace likely/unlikely profiler" is that this is not a
637 histogram of the callers, but actual 572 histogram of the callers, but actually places the calling
638 events into a running trace buffer t 573 events into a running trace buffer to see when and where the
639 events happened, as well as their re 574 events happened, as well as their results.
640 575
641 Say N if unsure. 576 Say N if unsure.
642 577
643 config BLK_DEV_IO_TRACE 578 config BLK_DEV_IO_TRACE
644 bool "Support for tracing block IO act 579 bool "Support for tracing block IO actions"
645 depends on SYSFS 580 depends on SYSFS
646 depends on BLOCK 581 depends on BLOCK
647 select RELAY 582 select RELAY
648 select DEBUG_FS 583 select DEBUG_FS
649 select TRACEPOINTS 584 select TRACEPOINTS
650 select GENERIC_TRACER 585 select GENERIC_TRACER
651 select STACKTRACE 586 select STACKTRACE
652 help 587 help
653 Say Y here if you want to be able to 588 Say Y here if you want to be able to trace the block layer actions
654 on a given queue. Tracing allows you 589 on a given queue. Tracing allows you to see any traffic happening
655 on a block device queue. For more in 590 on a block device queue. For more information (and the userspace
656 support tools needed), fetch the blk 591 support tools needed), fetch the blktrace tools from:
657 592
658 git://git.kernel.dk/blktrace.git 593 git://git.kernel.dk/blktrace.git
659 594
660 Tracing also is possible using the f 595 Tracing also is possible using the ftrace interface, e.g.:
661 596
662 echo 1 > /sys/block/sda/sda1/trace 597 echo 1 > /sys/block/sda/sda1/trace/enable
663 echo blk > /sys/kernel/tracing/cur !! 598 echo blk > /sys/kernel/debug/tracing/current_tracer
664 cat /sys/kernel/tracing/trace_pipe !! 599 cat /sys/kernel/debug/tracing/trace_pipe
665 600
666 If unsure, say N. 601 If unsure, say N.
667 602
668 config FPROBE_EVENTS <<
669 depends on FPROBE <<
670 depends on HAVE_REGS_AND_STACK_ACCESS_ <<
671 bool "Enable fprobe-based dynamic even <<
672 select TRACING <<
673 select PROBE_EVENTS <<
674 select DYNAMIC_EVENTS <<
675 default y <<
676 help <<
677 This allows user to add tracing even <<
678 exit via ftrace interface. The synta <<
679 and the kprobe events on function en <<
680 transparently converted to this fpro <<
681 <<
682 config PROBE_EVENTS_BTF_ARGS <<
683 depends on HAVE_FUNCTION_ARG_ACCESS_AP <<
684 depends on FPROBE_EVENTS || KPROBE_EVE <<
685 depends on DEBUG_INFO_BTF && BPF_SYSCA <<
686 bool "Support BTF function arguments f <<
687 default y <<
688 help <<
689 The user can specify the arguments o <<
690 of the arguments of the probed funct <<
691 kernel function entry or a tracepoin <<
692 This is available only if BTF (BPF T <<
693 <<
694 config KPROBE_EVENTS 603 config KPROBE_EVENTS
695 depends on KPROBES 604 depends on KPROBES
696 depends on HAVE_REGS_AND_STACK_ACCESS_ 605 depends on HAVE_REGS_AND_STACK_ACCESS_API
697 bool "Enable kprobes-based dynamic eve 606 bool "Enable kprobes-based dynamic events"
698 select TRACING 607 select TRACING
699 select PROBE_EVENTS 608 select PROBE_EVENTS
700 select DYNAMIC_EVENTS 609 select DYNAMIC_EVENTS
701 default y 610 default y
702 help 611 help
703 This allows the user to add tracing 612 This allows the user to add tracing events (similar to tracepoints)
704 on the fly via the ftrace interface. 613 on the fly via the ftrace interface. See
705 Documentation/trace/kprobetrace.rst 614 Documentation/trace/kprobetrace.rst for more details.
706 615
707 Those events can be inserted whereve 616 Those events can be inserted wherever kprobes can probe, and record
708 various register and memory values. 617 various register and memory values.
709 618
710 This option is also required by perf 619 This option is also required by perf-probe subcommand of perf tools.
711 If you want to use perf tools, this 620 If you want to use perf tools, this option is strongly recommended.
712 621
713 config KPROBE_EVENTS_ON_NOTRACE 622 config KPROBE_EVENTS_ON_NOTRACE
714 bool "Do NOT protect notrace function 623 bool "Do NOT protect notrace function from kprobe events"
715 depends on KPROBE_EVENTS 624 depends on KPROBE_EVENTS
716 depends on DYNAMIC_FTRACE 625 depends on DYNAMIC_FTRACE
717 default n 626 default n
718 help 627 help
719 This is only for the developers who 628 This is only for the developers who want to debug ftrace itself
720 using kprobe events. 629 using kprobe events.
721 630
722 If kprobes can use ftrace instead of 631 If kprobes can use ftrace instead of breakpoint, ftrace related
723 functions are protected from kprobe- 632 functions are protected from kprobe-events to prevent an infinite
724 recursion or any unexpected executio 633 recursion or any unexpected execution path which leads to a kernel
725 crash. 634 crash.
726 635
727 This option disables such protection 636 This option disables such protection and allows you to put kprobe
728 events on ftrace functions for debug 637 events on ftrace functions for debugging ftrace by itself.
729 Note that this might let you shoot y 638 Note that this might let you shoot yourself in the foot.
730 639
731 If unsure, say N. 640 If unsure, say N.
732 641
733 config UPROBE_EVENTS 642 config UPROBE_EVENTS
734 bool "Enable uprobes-based dynamic eve 643 bool "Enable uprobes-based dynamic events"
735 depends on ARCH_SUPPORTS_UPROBES 644 depends on ARCH_SUPPORTS_UPROBES
736 depends on MMU 645 depends on MMU
737 depends on PERF_EVENTS 646 depends on PERF_EVENTS
738 select UPROBES 647 select UPROBES
739 select PROBE_EVENTS 648 select PROBE_EVENTS
740 select DYNAMIC_EVENTS 649 select DYNAMIC_EVENTS
741 select TRACING 650 select TRACING
742 default y 651 default y
743 help 652 help
744 This allows the user to add tracing 653 This allows the user to add tracing events on top of userspace
745 dynamic events (similar to tracepoin 654 dynamic events (similar to tracepoints) on the fly via the trace
746 events interface. Those events can b 655 events interface. Those events can be inserted wherever uprobes
747 can probe, and record various regist 656 can probe, and record various registers.
748 This option is required if you plan 657 This option is required if you plan to use perf-probe subcommand
749 of perf tools on user space applicat 658 of perf tools on user space applications.
750 659
751 config BPF_EVENTS 660 config BPF_EVENTS
752 depends on BPF_SYSCALL 661 depends on BPF_SYSCALL
753 depends on (KPROBE_EVENTS || UPROBE_EV 662 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
754 bool 663 bool
755 default y 664 default y
756 help 665 help
757 This allows the user to attach BPF p 666 This allows the user to attach BPF programs to kprobe, uprobe, and
758 tracepoint events. 667 tracepoint events.
759 668
760 config DYNAMIC_EVENTS 669 config DYNAMIC_EVENTS
761 def_bool n 670 def_bool n
762 671
763 config PROBE_EVENTS 672 config PROBE_EVENTS
764 def_bool n 673 def_bool n
765 674
766 config BPF_KPROBE_OVERRIDE 675 config BPF_KPROBE_OVERRIDE
767 bool "Enable BPF programs to override 676 bool "Enable BPF programs to override a kprobed function"
768 depends on BPF_EVENTS 677 depends on BPF_EVENTS
769 depends on FUNCTION_ERROR_INJECTION 678 depends on FUNCTION_ERROR_INJECTION
770 default n 679 default n
771 help 680 help
772 Allows BPF to override the execution 681 Allows BPF to override the execution of a probed function and
773 set a different return value. This i 682 set a different return value. This is used for error injection.
774 683
775 config FTRACE_MCOUNT_RECORD 684 config FTRACE_MCOUNT_RECORD
776 def_bool y 685 def_bool y
777 depends on DYNAMIC_FTRACE 686 depends on DYNAMIC_FTRACE
778 depends on HAVE_FTRACE_MCOUNT_RECORD 687 depends on HAVE_FTRACE_MCOUNT_RECORD
779 688
780 config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_EN 689 config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
781 bool 690 bool
782 depends on FTRACE_MCOUNT_RECORD 691 depends on FTRACE_MCOUNT_RECORD
783 692
784 config FTRACE_MCOUNT_USE_CC 693 config FTRACE_MCOUNT_USE_CC
785 def_bool y 694 def_bool y
786 depends on $(cc-option,-mrecord-mcount 695 depends on $(cc-option,-mrecord-mcount)
787 depends on !FTRACE_MCOUNT_USE_PATCHABL 696 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
788 depends on FTRACE_MCOUNT_RECORD 697 depends on FTRACE_MCOUNT_RECORD
789 698
790 config FTRACE_MCOUNT_USE_OBJTOOL 699 config FTRACE_MCOUNT_USE_OBJTOOL
791 def_bool y 700 def_bool y
792 depends on HAVE_OBJTOOL_MCOUNT 701 depends on HAVE_OBJTOOL_MCOUNT
793 depends on !FTRACE_MCOUNT_USE_PATCHABL 702 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
794 depends on !FTRACE_MCOUNT_USE_CC 703 depends on !FTRACE_MCOUNT_USE_CC
795 depends on FTRACE_MCOUNT_RECORD 704 depends on FTRACE_MCOUNT_RECORD
796 select OBJTOOL <<
797 705
798 config FTRACE_MCOUNT_USE_RECORDMCOUNT 706 config FTRACE_MCOUNT_USE_RECORDMCOUNT
799 def_bool y 707 def_bool y
800 depends on !FTRACE_MCOUNT_USE_PATCHABL 708 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
801 depends on !FTRACE_MCOUNT_USE_CC 709 depends on !FTRACE_MCOUNT_USE_CC
802 depends on !FTRACE_MCOUNT_USE_OBJTOOL 710 depends on !FTRACE_MCOUNT_USE_OBJTOOL
803 depends on FTRACE_MCOUNT_RECORD 711 depends on FTRACE_MCOUNT_RECORD
804 712
805 config TRACING_MAP 713 config TRACING_MAP
806 bool 714 bool
807 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 715 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
808 help 716 help
809 tracing_map is a special-purpose loc 717 tracing_map is a special-purpose lock-free map for tracing,
810 separated out as a stand-alone facil 718 separated out as a stand-alone facility in order to allow it
811 to be shared between multiple tracer 719 to be shared between multiple tracers. It isn't meant to be
812 generally used outside of that conte 720 generally used outside of that context, and is normally
813 selected by tracers that use it. 721 selected by tracers that use it.
814 722
815 config SYNTH_EVENTS 723 config SYNTH_EVENTS
816 bool "Synthetic trace events" 724 bool "Synthetic trace events"
817 select TRACING 725 select TRACING
818 select DYNAMIC_EVENTS 726 select DYNAMIC_EVENTS
819 default n 727 default n
820 help 728 help
821 Synthetic events are user-defined tr 729 Synthetic events are user-defined trace events that can be
822 used to combine data from other trac 730 used to combine data from other trace events or in fact any
823 data source. Synthetic events can b 731 data source. Synthetic events can be generated indirectly
824 via the trace() action of histogram 732 via the trace() action of histogram triggers or directly
825 by way of an in-kernel API. 733 by way of an in-kernel API.
826 734
827 See Documentation/trace/events.rst o 735 See Documentation/trace/events.rst or
828 Documentation/trace/histogram.rst fo 736 Documentation/trace/histogram.rst for details and examples.
829 737
830 If in doubt, say N. 738 If in doubt, say N.
831 739
832 config USER_EVENTS <<
833 bool "User trace events" <<
834 select TRACING <<
835 select DYNAMIC_EVENTS <<
836 help <<
837 User trace events are user-defined t <<
838 can be used like an existing kernel <<
839 events are generated by writing to a <<
840 processes can determine if their tra <<
841 generated by registering a value and <<
842 that reflects when it is enabled or <<
843 <<
844 See Documentation/trace/user_events. <<
845 If in doubt, say N. <<
846 <<
847 config HIST_TRIGGERS 740 config HIST_TRIGGERS
848 bool "Histogram triggers" 741 bool "Histogram triggers"
849 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG 742 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
850 select TRACING_MAP 743 select TRACING_MAP
851 select TRACING 744 select TRACING
852 select DYNAMIC_EVENTS 745 select DYNAMIC_EVENTS
853 select SYNTH_EVENTS 746 select SYNTH_EVENTS
854 default n 747 default n
855 help 748 help
856 Hist triggers allow one or more arbi 749 Hist triggers allow one or more arbitrary trace event fields
857 to be aggregated into hash tables an 750 to be aggregated into hash tables and dumped to stdout by
858 reading a debugfs/tracefs file. The 751 reading a debugfs/tracefs file. They're useful for
859 gathering quick and dirty (though pr 752 gathering quick and dirty (though precise) summaries of
860 event activity as an initial guide f 753 event activity as an initial guide for further investigation
861 using more advanced tools. 754 using more advanced tools.
862 755
863 Inter-event tracing of quantities su 756 Inter-event tracing of quantities such as latencies is also
864 supported using hist triggers under 757 supported using hist triggers under this option.
865 758
866 See Documentation/trace/histogram.rs 759 See Documentation/trace/histogram.rst.
867 If in doubt, say N. 760 If in doubt, say N.
868 761
869 config TRACE_EVENT_INJECT 762 config TRACE_EVENT_INJECT
870 bool "Trace event injection" 763 bool "Trace event injection"
871 depends on TRACING 764 depends on TRACING
872 help 765 help
873 Allow user-space to inject a specifi 766 Allow user-space to inject a specific trace event into the ring
874 buffer. This is mainly used for test 767 buffer. This is mainly used for testing purpose.
875 768
876 If unsure, say N. 769 If unsure, say N.
877 770
878 config TRACEPOINT_BENCHMARK 771 config TRACEPOINT_BENCHMARK
879 bool "Add tracepoint that benchmarks t 772 bool "Add tracepoint that benchmarks tracepoints"
880 help 773 help
881 This option creates the tracepoint "b 774 This option creates the tracepoint "benchmark:benchmark_event".
882 When the tracepoint is enabled, it ki 775 When the tracepoint is enabled, it kicks off a kernel thread that
883 goes into an infinite loop (calling c 776 goes into an infinite loop (calling cond_resched() to let other tasks
884 run), and calls the tracepoint. Each 777 run), and calls the tracepoint. Each iteration will record the time
885 it took to write to the tracepoint an 778 it took to write to the tracepoint and the next iteration that
886 data will be passed to the tracepoint 779 data will be passed to the tracepoint itself. That is, the tracepoint
887 will report the time it took to do th 780 will report the time it took to do the previous tracepoint.
888 The string written to the tracepoint 781 The string written to the tracepoint is a static string of 128 bytes
889 to keep the time the same. The initia 782 to keep the time the same. The initial string is simply a write of
890 "START". The second string records th 783 "START". The second string records the cold cache time of the first
891 write which is not added to the rest 784 write which is not added to the rest of the calculations.
892 785
893 As it is a tight loop, it benchmarks 786 As it is a tight loop, it benchmarks as hot cache. That's fine because
894 we care most about hot paths that are 787 we care most about hot paths that are probably in cache already.
895 788
896 An example of the output: 789 An example of the output:
897 790
898 START 791 START
899 first=3672 [COLD CACHED] 792 first=3672 [COLD CACHED]
900 last=632 first=3672 max=632 min= 793 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
901 last=278 first=3672 max=632 min= 794 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
902 last=277 first=3672 max=632 min= 795 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
903 last=273 first=3672 max=632 min= 796 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
904 last=273 first=3672 max=632 min= 797 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
905 last=281 first=3672 max=632 min= 798 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
906 799
907 800
908 config RING_BUFFER_BENCHMARK 801 config RING_BUFFER_BENCHMARK
909 tristate "Ring buffer benchmark stress 802 tristate "Ring buffer benchmark stress tester"
910 depends on RING_BUFFER 803 depends on RING_BUFFER
911 help 804 help
912 This option creates a test to stress 805 This option creates a test to stress the ring buffer and benchmark it.
913 It creates its own ring buffer such 806 It creates its own ring buffer such that it will not interfere with
914 any other users of the ring buffer ( 807 any other users of the ring buffer (such as ftrace). It then creates
915 a producer and consumer that will ru 808 a producer and consumer that will run for 10 seconds and sleep for
916 10 seconds. Each interval it will pr 809 10 seconds. Each interval it will print out the number of events
917 it recorded and give a rough estimat 810 it recorded and give a rough estimate of how long each iteration took.
918 811
919 It does not disable interrupts or ra 812 It does not disable interrupts or raise its priority, so it may be
920 affected by processes that are runni 813 affected by processes that are running.
921 814
922 If unsure, say N. 815 If unsure, say N.
923 816
924 config TRACE_EVAL_MAP_FILE 817 config TRACE_EVAL_MAP_FILE
925 bool "Show eval mappings for trace even 818 bool "Show eval mappings for trace events"
926 depends on TRACING 819 depends on TRACING
927 help 820 help
928 The "print fmt" of the trace events wi 821 The "print fmt" of the trace events will show the enum/sizeof names
929 instead of their values. This can caus 822 instead of their values. This can cause problems for user space tools
930 that use this string to parse the raw 823 that use this string to parse the raw data as user space does not know
931 how to convert the string to its value 824 how to convert the string to its value.
932 825
933 To fix this, there's a special macro i 826 To fix this, there's a special macro in the kernel that can be used
934 to convert an enum/sizeof into its val 827 to convert an enum/sizeof into its value. If this macro is used, then
935 the print fmt strings will be converte 828 the print fmt strings will be converted to their values.
936 829
937 If something does not get converted pr 830 If something does not get converted properly, this option can be
938 used to show what enums/sizeof the ker 831 used to show what enums/sizeof the kernel tried to convert.
939 832
940 This option is for debugging the conve 833 This option is for debugging the conversions. A file is created
941 in the tracing directory called "eval_ 834 in the tracing directory called "eval_map" that will show the
942 names matched with their values and wh 835 names matched with their values and what trace event system they
943 belong too. 836 belong too.
944 837
945 Normally, the mapping of the strings t 838 Normally, the mapping of the strings to values will be freed after
946 boot up or module load. With this opti 839 boot up or module load. With this option, they will not be freed, as
947 they are needed for the "eval_map" fil 840 they are needed for the "eval_map" file. Enabling this option will
948 increase the memory footprint of the r 841 increase the memory footprint of the running kernel.
949 842
950 If unsure, say N. 843 If unsure, say N.
951 844
952 config FTRACE_RECORD_RECURSION 845 config FTRACE_RECORD_RECURSION
953 bool "Record functions that recurse in 846 bool "Record functions that recurse in function tracing"
954 depends on FUNCTION_TRACER 847 depends on FUNCTION_TRACER
955 help 848 help
956 All callbacks that attach to the fun 849 All callbacks that attach to the function tracing have some sort
957 of protection against recursion. Eve 850 of protection against recursion. Even though the protection exists,
958 it adds overhead. This option will c 851 it adds overhead. This option will create a file in the tracefs
959 file system called "recursed_functio 852 file system called "recursed_functions" that will list the functions
960 that triggered a recursion. 853 that triggered a recursion.
961 854
962 This will add more overhead to cases 855 This will add more overhead to cases that have recursion.
963 856
964 If unsure, say N 857 If unsure, say N
965 858
966 config FTRACE_RECORD_RECURSION_SIZE 859 config FTRACE_RECORD_RECURSION_SIZE
967 int "Max number of recursed functions 860 int "Max number of recursed functions to record"
968 default 128 !! 861 default 128
969 depends on FTRACE_RECORD_RECURSION 862 depends on FTRACE_RECORD_RECURSION
970 help 863 help
971 This defines the limit of number of 864 This defines the limit of number of functions that can be
972 listed in the "recursed_functions" f 865 listed in the "recursed_functions" file, that lists all
973 the functions that caused a recursio 866 the functions that caused a recursion to happen.
974 This file can be reset, but the limi 867 This file can be reset, but the limit can not change in
975 size at runtime. 868 size at runtime.
976 869
977 config FTRACE_VALIDATE_RCU_IS_WATCHING <<
978 bool "Validate RCU is on during ftrace <<
979 depends on FUNCTION_TRACER <<
980 depends on ARCH_WANTS_NO_INSTR <<
981 help <<
982 All callbacks that attach to the fun <<
983 protection against recursion. This o <<
984 ftrace (and other users of ftrace_te <<
985 called outside of RCU, as if they ar <<
986 also has a noticeable overhead when <<
987 <<
988 If unsure, say N <<
989 <<
990 config RING_BUFFER_RECORD_RECURSION 870 config RING_BUFFER_RECORD_RECURSION
991 bool "Record functions that recurse in 871 bool "Record functions that recurse in the ring buffer"
992 depends on FTRACE_RECORD_RECURSION 872 depends on FTRACE_RECORD_RECURSION
993 # default y, because it is coupled wit 873 # default y, because it is coupled with FTRACE_RECORD_RECURSION
994 default y 874 default y
995 help 875 help
996 The ring buffer has its own internal 876 The ring buffer has its own internal recursion. Although when
997 recursion happens it won't cause har !! 877 recursion happens it wont cause harm because of the protection,
998 but it does cause unwanted overhead. !! 878 but it does cause an unwanted overhead. Enabling this option will
999 place where recursion was detected i 879 place where recursion was detected into the ftrace "recursed_functions"
1000 file. 880 file.
1001 881
1002 This will add more overhead to case 882 This will add more overhead to cases that have recursion.
1003 883
1004 config GCOV_PROFILE_FTRACE 884 config GCOV_PROFILE_FTRACE
1005 bool "Enable GCOV profiling on ftrace 885 bool "Enable GCOV profiling on ftrace subsystem"
1006 depends on GCOV_KERNEL 886 depends on GCOV_KERNEL
1007 help 887 help
1008 Enable GCOV profiling on ftrace sub 888 Enable GCOV profiling on ftrace subsystem for checking
1009 which functions/lines are tested. 889 which functions/lines are tested.
1010 890
1011 If unsure, say N. 891 If unsure, say N.
1012 892
1013 Note that on a kernel compiled with 893 Note that on a kernel compiled with this config, ftrace will
1014 run significantly slower. 894 run significantly slower.
1015 895
1016 config FTRACE_SELFTEST 896 config FTRACE_SELFTEST
1017 bool 897 bool
1018 898
1019 config FTRACE_STARTUP_TEST 899 config FTRACE_STARTUP_TEST
1020 bool "Perform a startup test on ftrac 900 bool "Perform a startup test on ftrace"
1021 depends on GENERIC_TRACER 901 depends on GENERIC_TRACER
1022 select FTRACE_SELFTEST 902 select FTRACE_SELFTEST
1023 help 903 help
1024 This option performs a series of st 904 This option performs a series of startup tests on ftrace. On bootup
1025 a series of tests are made to verif 905 a series of tests are made to verify that the tracer is
1026 functioning properly. It will do te 906 functioning properly. It will do tests on all the configured
1027 tracers of ftrace. 907 tracers of ftrace.
1028 908
1029 config EVENT_TRACE_STARTUP_TEST 909 config EVENT_TRACE_STARTUP_TEST
1030 bool "Run selftest on trace events" 910 bool "Run selftest on trace events"
1031 depends on FTRACE_STARTUP_TEST 911 depends on FTRACE_STARTUP_TEST
1032 default y 912 default y
1033 help 913 help
1034 This option performs a test on all 914 This option performs a test on all trace events in the system.
1035 It basically just enables each even 915 It basically just enables each event and runs some code that
1036 will trigger events (not necessaril 916 will trigger events (not necessarily the event it enables)
1037 This may take some time run as ther 917 This may take some time run as there are a lot of events.
1038 918
1039 config EVENT_TRACE_TEST_SYSCALLS 919 config EVENT_TRACE_TEST_SYSCALLS
1040 bool "Run selftest on syscall events" 920 bool "Run selftest on syscall events"
1041 depends on EVENT_TRACE_STARTUP_TEST 921 depends on EVENT_TRACE_STARTUP_TEST
1042 help 922 help
1043 This option will also enable testing 923 This option will also enable testing every syscall event.
1044 It only enables the event and disabl 924 It only enables the event and disables it and runs various loads
1045 with the event enabled. This adds a 925 with the event enabled. This adds a bit more time for kernel boot
1046 up since it runs this on every syste 926 up since it runs this on every system call defined.
1047 927
1048 TBD - enable a way to actually call 928 TBD - enable a way to actually call the syscalls as we test their
1049 events 929 events
1050 930
1051 config FTRACE_SORT_STARTUP_TEST 931 config FTRACE_SORT_STARTUP_TEST
1052 bool "Verify compile time sorting of f 932 bool "Verify compile time sorting of ftrace functions"
1053 depends on DYNAMIC_FTRACE 933 depends on DYNAMIC_FTRACE
1054 depends on BUILDTIME_MCOUNT_SORT 934 depends on BUILDTIME_MCOUNT_SORT
1055 help 935 help
1056 Sorting of the mcount_loc sections t 936 Sorting of the mcount_loc sections that is used to find the
1057 where the ftrace knows where to patc 937 where the ftrace knows where to patch functions for tracing
1058 and other callbacks is done at compi 938 and other callbacks is done at compile time. But if the sort
1059 is not done correctly, it will cause 939 is not done correctly, it will cause non-deterministic failures.
1060 When this is set, the sorted section 940 When this is set, the sorted sections will be verified that they
1061 are in deed sorted and will warn if 941 are in deed sorted and will warn if they are not.
1062 942
1063 If unsure, say N 943 If unsure, say N
1064 944
1065 config RING_BUFFER_STARTUP_TEST 945 config RING_BUFFER_STARTUP_TEST
1066 bool "Ring buffer startup self test" 946 bool "Ring buffer startup self test"
1067 depends on RING_BUFFER 947 depends on RING_BUFFER
1068 help 948 help
1069 Run a simple self test on the ring b 949 Run a simple self test on the ring buffer on boot up. Late in the
1070 kernel boot sequence, the test will 950 kernel boot sequence, the test will start that kicks off
1071 a thread per cpu. Each thread will w 951 a thread per cpu. Each thread will write various size events
1072 into the ring buffer. Another thread 952 into the ring buffer. Another thread is created to send IPIs
1073 to each of the threads, where the IP 953 to each of the threads, where the IPI handler will also write
1074 to the ring buffer, to test/stress t 954 to the ring buffer, to test/stress the nesting ability.
1075 If any anomalies are discovered, a w 955 If any anomalies are discovered, a warning will be displayed
1076 and all ring buffers will be disable 956 and all ring buffers will be disabled.
1077 957
1078 The test runs for 10 seconds. This w 958 The test runs for 10 seconds. This will slow your boot time
1079 by at least 10 more seconds. 959 by at least 10 more seconds.
1080 960
1081 At the end of the test, statistics a !! 961 At the end of the test, statics and more checks are done.
1082 It will output the stats of each per !! 962 It will output the stats of each per cpu buffer. What
1083 was written, the sizes, what was rea 963 was written, the sizes, what was read, what was lost, and
1084 other similar details. 964 other similar details.
1085 965
1086 If unsure, say N 966 If unsure, say N
1087 967
1088 config RING_BUFFER_VALIDATE_TIME_DELTAS 968 config RING_BUFFER_VALIDATE_TIME_DELTAS
1089 bool "Verify ring buffer time stamp d 969 bool "Verify ring buffer time stamp deltas"
1090 depends on RING_BUFFER 970 depends on RING_BUFFER
1091 help 971 help
1092 This will audit the time stamps on 972 This will audit the time stamps on the ring buffer sub
1093 buffer to make sure that all the ti 973 buffer to make sure that all the time deltas for the
1094 events on a sub buffer matches the 974 events on a sub buffer matches the current time stamp.
1095 This audit is performed for every e 975 This audit is performed for every event that is not
1096 interrupted, or interrupting anothe 976 interrupted, or interrupting another event. A check
1097 is also made when traversing sub bu 977 is also made when traversing sub buffers to make sure
1098 that all the deltas on the previous 978 that all the deltas on the previous sub buffer do not
1099 add up to be greater than the curre 979 add up to be greater than the current time stamp.
1100 980
1101 NOTE: This adds significant overhea 981 NOTE: This adds significant overhead to recording of events,
1102 and should only be used to test the 982 and should only be used to test the logic of the ring buffer.
1103 Do not use it on production systems 983 Do not use it on production systems.
1104 984
1105 Only say Y if you understand what t 985 Only say Y if you understand what this does, and you
1106 still want it enabled. Otherwise sa 986 still want it enabled. Otherwise say N
1107 987
1108 config MMIOTRACE_TEST 988 config MMIOTRACE_TEST
1109 tristate "Test module for mmiotrace" 989 tristate "Test module for mmiotrace"
1110 depends on MMIOTRACE && m 990 depends on MMIOTRACE && m
1111 help 991 help
1112 This is a dumb module for testing m 992 This is a dumb module for testing mmiotrace. It is very dangerous
1113 as it will write garbage to IO memo 993 as it will write garbage to IO memory starting at a given address.
1114 However, it should be safe to use o 994 However, it should be safe to use on e.g. unused portion of VRAM.
1115 995
1116 Say N, unless you absolutely know w 996 Say N, unless you absolutely know what you are doing.
1117 997
1118 config PREEMPTIRQ_DELAY_TEST 998 config PREEMPTIRQ_DELAY_TEST
1119 tristate "Test module to create a pre 999 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
1120 depends on m 1000 depends on m
1121 help 1001 help
1122 Select this option to build a test 1002 Select this option to build a test module that can help test latency
1123 tracers by executing a preempt or i 1003 tracers by executing a preempt or irq disable section with a user
1124 configurable delay. The module busy 1004 configurable delay. The module busy waits for the duration of the
1125 critical section. 1005 critical section.
1126 1006
1127 For example, the following invocati 1007 For example, the following invocation generates a burst of three
1128 irq-disabled critical sections for 1008 irq-disabled critical sections for 500us:
1129 modprobe preemptirq_delay_test test 1009 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
1130 1010
1131 What's more, if you want to attach 1011 What's more, if you want to attach the test on the cpu which the latency
1132 tracer is running on, specify cpu_a 1012 tracer is running on, specify cpu_affinity=cpu_num at the end of the
1133 command. 1013 command.
1134 1014
1135 If unsure, say N 1015 If unsure, say N
1136 1016
1137 config SYNTH_EVENT_GEN_TEST 1017 config SYNTH_EVENT_GEN_TEST
1138 tristate "Test module for in-kernel s 1018 tristate "Test module for in-kernel synthetic event generation"
1139 depends on SYNTH_EVENTS && m !! 1019 depends on SYNTH_EVENTS
1140 help 1020 help
1141 This option creates a test module t 1021 This option creates a test module to check the base
1142 functionality of in-kernel syntheti 1022 functionality of in-kernel synthetic event definition and
1143 generation. 1023 generation.
1144 1024
1145 To test, insert the module, and the 1025 To test, insert the module, and then check the trace buffer
1146 for the generated sample events. 1026 for the generated sample events.
1147 1027
1148 If unsure, say N. 1028 If unsure, say N.
1149 1029
1150 config KPROBE_EVENT_GEN_TEST 1030 config KPROBE_EVENT_GEN_TEST
1151 tristate "Test module for in-kernel k 1031 tristate "Test module for in-kernel kprobe event generation"
1152 depends on KPROBE_EVENTS && m !! 1032 depends on KPROBE_EVENTS
1153 help 1033 help
1154 This option creates a test module t 1034 This option creates a test module to check the base
1155 functionality of in-kernel kprobe e 1035 functionality of in-kernel kprobe event definition.
1156 1036
1157 To test, insert the module, and the 1037 To test, insert the module, and then check the trace buffer
1158 for the generated kprobe events. 1038 for the generated kprobe events.
1159 1039
1160 If unsure, say N. 1040 If unsure, say N.
1161 1041
1162 config HIST_TRIGGERS_DEBUG 1042 config HIST_TRIGGERS_DEBUG
1163 bool "Hist trigger debug support" 1043 bool "Hist trigger debug support"
1164 depends on HIST_TRIGGERS 1044 depends on HIST_TRIGGERS
1165 help 1045 help
1166 Add "hist_debug" file for each even 1046 Add "hist_debug" file for each event, which when read will
1167 dump out a bunch of internal detail 1047 dump out a bunch of internal details about the hist triggers
1168 defined on that event. 1048 defined on that event.
1169 1049
1170 The hist_debug file serves a couple 1050 The hist_debug file serves a couple of purposes:
1171 1051
1172 - Helps developers verify that no 1052 - Helps developers verify that nothing is broken.
1173 1053
1174 - Provides educational informatio 1054 - Provides educational information to support the details
1175 of the hist trigger internals a 1055 of the hist trigger internals as described by
1176 Documentation/trace/histogram-d 1056 Documentation/trace/histogram-design.rst.
1177 1057
1178 The hist_debug output only covers t 1058 The hist_debug output only covers the data structures
1179 related to the histogram definition 1059 related to the histogram definitions themselves and doesn't
1180 display the internals of map bucket 1060 display the internals of map buckets or variable values of
1181 running histograms. 1061 running histograms.
1182 1062
1183 If unsure, say N. 1063 If unsure, say N.
1184 <<
1185 source "kernel/trace/rv/Kconfig" <<
1186 1064
1187 endif # FTRACE 1065 endif # FTRACE
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