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