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