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Thomas Gleixnerec8f24b2019-05-19 13:07:45 +01001# SPDX-License-Identifier: GPL-2.0-only
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02002#
Steven Rostedt606576c2008-10-06 19:06:12 -04003# Architectures that offer an FUNCTION_TRACER implementation should
4# select HAVE_FUNCTION_TRACER:
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +02005#
Frédéric Weisbecker2a3a4f62008-09-21 20:12:14 +02006
Török Edwin8d264872008-11-23 12:39:08 +02007config USER_STACKTRACE_SUPPORT
8 bool
9
Frédéric Weisbecker2a3a4f62008-09-21 20:12:14 +020010config NOP_TRACER
11 bool
12
Steven Rostedt606576c2008-10-06 19:06:12 -040013config HAVE_FUNCTION_TRACER
Arnaldo Carvalho de Melo16444a82008-05-12 21:20:42 +020014 bool
Mike Frysinger555f3862009-09-14 20:10:15 -040015 help
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -030016 See Documentation/trace/ftrace-design.rst
Steven Rostedtbc0c38d2008-05-12 21:20:42 +020017
Frederic Weisbeckerfb526072008-11-25 21:07:04 +010018config HAVE_FUNCTION_GRAPH_TRACER
Frederic Weisbecker15e6cb32008-11-11 07:14:25 +010019 bool
Mike Frysinger555f3862009-09-14 20:10:15 -040020 help
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -030021 See Documentation/trace/ftrace-design.rst
Frederic Weisbecker15e6cb32008-11-11 07:14:25 +010022
Steven Rostedt677aa9f2008-05-17 00:01:36 -040023config HAVE_DYNAMIC_FTRACE
24 bool
Mike Frysinger555f3862009-09-14 20:10:15 -040025 help
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -030026 See Documentation/trace/ftrace-design.rst
Steven Rostedt677aa9f2008-05-17 00:01:36 -040027
Masami Hiramatsu06aeaae2012-09-28 17:15:17 +090028config HAVE_DYNAMIC_FTRACE_WITH_REGS
29 bool
30
Steven Rostedt (VMware)763e34e2019-11-08 13:07:06 -050031config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
32 bool
33
Steven Rostedt (VMware)02a474c2020-10-27 10:55:55 -040034config HAVE_DYNAMIC_FTRACE_WITH_ARGS
35 bool
36 help
37 If this is set, then arguments and stack can be found from
38 the pt_regs passed into the function callback regs parameter
39 by default, even without setting the REGS flag in the ftrace_ops.
40 This allows for use of regs_get_kernel_argument() and
41 kernel_stack_pointer().
42
Steven Rostedt8da38212008-08-14 15:45:07 -040043config HAVE_FTRACE_MCOUNT_RECORD
44 bool
Mike Frysinger555f3862009-09-14 20:10:15 -040045 help
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -030046 See Documentation/trace/ftrace-design.rst
Steven Rostedt8da38212008-08-14 15:45:07 -040047
Josh Stone66700002009-08-24 14:43:11 -070048config HAVE_SYSCALL_TRACEPOINTS
Frederic Weisbeckeree08c6e2009-03-07 05:52:59 +010049 bool
Mike Frysinger555f3862009-09-14 20:10:15 -040050 help
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -030051 See Documentation/trace/ftrace-design.rst
Frederic Weisbeckeree08c6e2009-03-07 05:52:59 +010052
Steven Rostedta2546fa2011-02-09 13:15:59 -050053config HAVE_FENTRY
54 bool
55 help
56 Arch supports the gcc options -pg with -mfentry
57
Vasily Gorbik2f4df002018-08-06 15:17:46 +020058config HAVE_NOP_MCOUNT
59 bool
60 help
61 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
62
Sami Tolvanen22c85422020-09-25 16:43:53 -070063config HAVE_OBJTOOL_MCOUNT
64 bool
65 help
66 Arch supports objtool --mcount
67
Steven Rostedtcf4db252010-10-14 23:32:44 -040068config HAVE_C_RECORDMCOUNT
Steven Rostedt72441cb2010-10-13 17:12:30 -040069 bool
70 help
71 C version of recordmcount available?
72
Steven Rostedt (Google)6b9b6412022-01-22 09:17:10 -050073config BUILDTIME_MCOUNT_SORT
74 bool
75 default y
76 depends on BUILDTIME_TABLE_SORT && !S390
77 help
78 Sort the mcount_loc section at build time.
79
Steven Rostedt352ad252008-05-12 21:20:42 +020080config TRACER_MAX_TRACE
81 bool
82
Josh Triplettea632e92012-09-02 19:45:14 -070083config TRACE_CLOCK
84 bool
85
Steven Rostedt7a8e76a2008-09-29 23:02:38 -040086config RING_BUFFER
87 bool
Josh Triplettea632e92012-09-02 19:45:14 -070088 select TRACE_CLOCK
Steven Rostedt (Red Hat)22287682013-05-03 11:16:18 -040089 select IRQ_WORK
Steven Rostedt7a8e76a2008-09-29 23:02:38 -040090
Tom Zanussi5f77a882009-04-08 03:14:01 -050091config EVENT_TRACING
Zhaoleib11c53e2009-05-25 18:11:59 +080092 select CONTEXT_SWITCH_TRACER
Krzysztof Kozlowskifc809bc2019-11-20 21:38:07 +080093 select GLOB
Zhaoleib11c53e2009-05-25 18:11:59 +080094 bool
95
96config CONTEXT_SWITCH_TRACER
Tom Zanussi5f77a882009-04-08 03:14:01 -050097 bool
98
Steven Rostedt85bac322009-09-04 14:24:40 -040099config RING_BUFFER_ALLOW_SWAP
100 bool
101 help
102 Allow the use of ring_buffer_swap_cpu.
103 Adds a very slight overhead to tracing when enabled.
104
Joel Fernandes (Google)c3bc8fd2018-07-30 15:24:23 -0700105config PREEMPTIRQ_TRACEPOINTS
106 bool
107 depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
108 select TRACING
109 default y
110 help
111 Create preempt/irq toggle tracepoints if needed, so that other parts
112 of the kernel can use them to generate or add hooks to them.
113
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400114# All tracer options should select GENERIC_TRACER. For those options that are
115# enabled by all tracers (context switch and event tracer) they select TRACING.
116# This allows those options to appear when no other tracer is selected. But the
117# options do not appear when something else selects it. We need the two options
118# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
Randy Dunlap40892362009-12-21 12:01:17 -0800119# hiding of the automatic options.
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400120
Steven Rostedtbc0c38d2008-05-12 21:20:42 +0200121config TRACING
122 bool
Steven Rostedt7a8e76a2008-09-29 23:02:38 -0400123 select RING_BUFFER
Al Viroc2c80522008-10-31 19:50:41 +0000124 select STACKTRACE if STACKTRACE_SUPPORT
Ingo Molnar5f87f112008-07-23 14:15:22 +0200125 select TRACEPOINTS
Steven Rostedtf3384b22008-10-29 11:15:57 -0400126 select NOP_TRACER
Frederic Weisbecker769b0442009-03-06 17:21:49 +0100127 select BINARY_PRINTF
Tom Zanussi5f77a882009-04-08 03:14:01 -0500128 select EVENT_TRACING
Josh Triplettea632e92012-09-02 19:45:14 -0700129 select TRACE_CLOCK
Steven Rostedtbc0c38d2008-05-12 21:20:42 +0200130
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400131config GENERIC_TRACER
132 bool
133 select TRACING
134
Ingo Molnar40ada302009-03-05 21:19:55 +0100135#
136# Minimum requirements an architecture has to meet for us to
137# be able to offer generic tracing facilities:
138#
139config TRACING_SUPPORT
140 bool
Michael Ellerman0ea5ee02018-05-02 21:29:48 +1000141 depends on TRACE_IRQFLAGS_SUPPORT
Ingo Molnar40ada302009-03-05 21:19:55 +0100142 depends on STACKTRACE_SUPPORT
KOSAKI Motohiro422d3c72009-03-06 10:40:53 +0900143 default y
Ingo Molnar40ada302009-03-05 21:19:55 +0100144
Steven Rostedt4ed9f072009-04-20 10:47:36 -0400145menuconfig FTRACE
146 bool "Tracers"
Masahiro Yamadade329512021-07-31 14:22:31 +0900147 depends on TRACING_SUPPORT
Steven Rostedt65b77242009-05-07 12:49:27 -0400148 default y if DEBUG_KERNEL
Steven Rostedt4ed9f072009-04-20 10:47:36 -0400149 help
Randy Dunlap40892362009-12-21 12:01:17 -0800150 Enable the kernel tracing infrastructure.
Steven Rostedt4ed9f072009-04-20 10:47:36 -0400151
152if FTRACE
Peter Zijlstra17d80fd2008-10-21 16:31:18 +0200153
Steven Rostedt (VMware)1e837942020-01-29 16:30:30 -0500154config BOOTTIME_TRACING
155 bool "Boot-time Tracing support"
Masami Hiramatsud8a953d2020-02-20 21:18:33 +0900156 depends on TRACING
157 select BOOT_CONFIG
Steven Rostedt (VMware)1e837942020-01-29 16:30:30 -0500158 help
159 Enable developer to setup ftrace subsystem via supplemental
160 kernel cmdline at boot time for debugging (tracing) driver
161 initialization and boot process.
162
Steven Rostedt606576c2008-10-06 19:06:12 -0400163config FUNCTION_TRACER
Steven Rostedt1b29b012008-05-12 21:20:42 +0200164 bool "Kernel Function Tracer"
Steven Rostedt606576c2008-10-06 19:06:12 -0400165 depends on HAVE_FUNCTION_TRACER
Steven Rostedt4d7a0772009-02-18 22:06:18 -0500166 select KALLSYMS
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400167 select GENERIC_TRACER
Steven Rostedt35e8e302008-05-12 21:20:42 +0200168 select CONTEXT_SWITCH_TRACER
Steven Rostedt (VMware)0598e4f2017-04-06 10:28:12 -0400169 select GLOB
Thomas Gleixner01b1d882019-07-26 23:19:38 +0200170 select TASKS_RCU if PREEMPTION
Paul E. McKenneye5a971d2020-04-03 12:10:28 -0700171 select TASKS_RUDE_RCU
Steven Rostedt1b29b012008-05-12 21:20:42 +0200172 help
173 Enable the kernel to trace every kernel function. This is done
174 by using a compiler feature to insert a small, 5-byte No-Operation
Randy Dunlap40892362009-12-21 12:01:17 -0800175 instruction at the beginning of every kernel function, which NOP
Steven Rostedt1b29b012008-05-12 21:20:42 +0200176 sequence is then dynamically patched into a tracer call when
177 tracing is enabled by the administrator. If it's runtime disabled
178 (the bootup default), then the overhead of the instructions is very
179 small and not measurable even in micro-benchmarks.
Steven Rostedt35e8e302008-05-12 21:20:42 +0200180
Frederic Weisbeckerfb526072008-11-25 21:07:04 +0100181config FUNCTION_GRAPH_TRACER
182 bool "Kernel Function Graph Tracer"
183 depends on HAVE_FUNCTION_GRAPH_TRACER
Frederic Weisbecker15e6cb32008-11-11 07:14:25 +0100184 depends on FUNCTION_TRACER
Steven Rostedteb4a0372009-06-18 12:53:21 -0400185 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
Ingo Molnar764f3b92008-12-03 10:33:58 +0100186 default y
Frederic Weisbecker15e6cb32008-11-11 07:14:25 +0100187 help
Frederic Weisbeckerfb526072008-11-25 21:07:04 +0100188 Enable the kernel to trace a function at both its return
189 and its entry.
Matt LaPlante692105b2009-01-26 11:12:25 +0100190 Its first purpose is to trace the duration of functions and
191 draw a call graph for each thread with some information like
Randy Dunlap40892362009-12-21 12:01:17 -0800192 the return value. This is done by setting the current return
Matt LaPlante692105b2009-01-26 11:12:25 +0100193 address on the current task structure into a stack of calls.
Frederic Weisbecker15e6cb32008-11-11 07:14:25 +0100194
Steven Rostedt (VMware)61778cd72020-01-29 16:19:10 -0500195config DYNAMIC_FTRACE
196 bool "enable/disable function tracing dynamically"
197 depends on FUNCTION_TRACER
198 depends on HAVE_DYNAMIC_FTRACE
199 default y
200 help
201 This option will modify all the calls to function tracing
202 dynamically (will patch them out of the binary image and
203 replace them with a No-Op instruction) on boot up. During
204 compile time, a table is made of all the locations that ftrace
205 can function trace, and this table is linked into the kernel
206 image. When this is enabled, functions can be individually
207 enabled, and the functions not enabled will not affect
208 performance of the system.
209
210 See the files in /sys/kernel/debug/tracing:
211 available_filter_functions
212 set_ftrace_filter
213 set_ftrace_notrace
214
215 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
216 otherwise has native performance as long as no tracing is active.
217
218config DYNAMIC_FTRACE_WITH_REGS
219 def_bool y
220 depends on DYNAMIC_FTRACE
221 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
222
223config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
224 def_bool y
Naveen N. Rao49a962c2020-11-26 23:38:39 +0530225 depends on DYNAMIC_FTRACE_WITH_REGS
Steven Rostedt (VMware)61778cd72020-01-29 16:19:10 -0500226 depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
227
Lukas Bulwahn12f99512021-08-06 21:50:27 +0200228config DYNAMIC_FTRACE_WITH_ARGS
229 def_bool y
230 depends on DYNAMIC_FTRACE
231 depends on HAVE_DYNAMIC_FTRACE_WITH_ARGS
232
Steven Rostedt (VMware)61778cd72020-01-29 16:19:10 -0500233config FUNCTION_PROFILER
234 bool "Kernel function profiler"
235 depends on FUNCTION_TRACER
236 default n
237 help
238 This option enables the kernel function profiler. A file is created
239 in debugfs called function_profile_enabled which defaults to zero.
240 When a 1 is echoed into this file profiling begins, and when a
241 zero is entered, profiling stops. A "functions" file is created in
242 the trace_stat directory; this file shows the list of functions that
243 have been hit and their counters.
244
245 If in doubt, say N.
246
247config STACK_TRACER
248 bool "Trace max stack"
249 depends on HAVE_FUNCTION_TRACER
250 select FUNCTION_TRACER
251 select STACKTRACE
252 select KALLSYMS
253 help
254 This special tracer records the maximum stack footprint of the
255 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
256
257 This tracer works by hooking into every function call that the
258 kernel executes, and keeping a maximum stack depth value and
259 stack-trace saved. If this is configured with DYNAMIC_FTRACE
260 then it will not have any overhead while the stack tracer
261 is disabled.
262
263 To enable the stack tracer on bootup, pass in 'stacktrace'
264 on the kernel command line.
265
266 The stack tracer can also be enabled or disabled via the
267 sysctl kernel.stack_tracer_enabled
268
269 Say N if unsure.
270
Joel Fernandes (Google)c3bc8fd2018-07-30 15:24:23 -0700271config TRACE_PREEMPT_TOGGLE
272 bool
273 help
274 Enables hooks which will be called when preemption is first disabled,
275 and last enabled.
Steven Rostedtbac429f2009-03-20 12:50:56 -0400276
Steven Rostedt81d68a92008-05-12 21:20:42 +0200277config IRQSOFF_TRACER
278 bool "Interrupts-off Latency Tracer"
279 default n
280 depends on TRACE_IRQFLAGS_SUPPORT
Steven Rostedt81d68a92008-05-12 21:20:42 +0200281 select TRACE_IRQFLAGS
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400282 select GENERIC_TRACER
Steven Rostedt81d68a92008-05-12 21:20:42 +0200283 select TRACER_MAX_TRACE
Steven Rostedt85bac322009-09-04 14:24:40 -0400284 select RING_BUFFER_ALLOW_SWAP
Steven Rostedt (Red Hat)22cffc22013-03-05 07:30:24 -0500285 select TRACER_SNAPSHOT
Steven Rostedt (Red Hat)0b85ffc2013-03-05 14:50:23 -0500286 select TRACER_SNAPSHOT_PER_CPU_SWAP
Steven Rostedt81d68a92008-05-12 21:20:42 +0200287 help
288 This option measures the time spent in irqs-off critical
289 sections, with microsecond accuracy.
290
291 The default measurement method is a maximum search, which is
292 disabled by default and can be runtime (re-)started
293 via:
294
GeunSik Lim156f5a72009-06-02 15:01:37 +0900295 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
Steven Rostedt81d68a92008-05-12 21:20:42 +0200296
Randy Dunlap40892362009-12-21 12:01:17 -0800297 (Note that kernel size and overhead increase with this option
Steven Rostedt6cd8a4b2008-05-12 21:20:42 +0200298 enabled. This option and the preempt-off timing option can be
299 used together or separately.)
300
301config PREEMPT_TRACER
302 bool "Preemption-off Latency Tracer"
303 default n
Thomas Gleixner30c93702019-07-26 23:19:40 +0200304 depends on PREEMPTION
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400305 select GENERIC_TRACER
Steven Rostedt6cd8a4b2008-05-12 21:20:42 +0200306 select TRACER_MAX_TRACE
Steven Rostedt85bac322009-09-04 14:24:40 -0400307 select RING_BUFFER_ALLOW_SWAP
Steven Rostedt (Red Hat)22cffc22013-03-05 07:30:24 -0500308 select TRACER_SNAPSHOT
Steven Rostedt (Red Hat)0b85ffc2013-03-05 14:50:23 -0500309 select TRACER_SNAPSHOT_PER_CPU_SWAP
Joel Fernandes (Google)c3bc8fd2018-07-30 15:24:23 -0700310 select TRACE_PREEMPT_TOGGLE
Steven Rostedt6cd8a4b2008-05-12 21:20:42 +0200311 help
Randy Dunlap40892362009-12-21 12:01:17 -0800312 This option measures the time spent in preemption-off critical
Steven Rostedt6cd8a4b2008-05-12 21:20:42 +0200313 sections, with microsecond accuracy.
314
315 The default measurement method is a maximum search, which is
316 disabled by default and can be runtime (re-)started
317 via:
318
GeunSik Lim156f5a72009-06-02 15:01:37 +0900319 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
Steven Rostedt6cd8a4b2008-05-12 21:20:42 +0200320
Randy Dunlap40892362009-12-21 12:01:17 -0800321 (Note that kernel size and overhead increase with this option
Steven Rostedt6cd8a4b2008-05-12 21:20:42 +0200322 enabled. This option and the irqs-off timing option can be
323 used together or separately.)
324
Steven Rostedt352ad252008-05-12 21:20:42 +0200325config SCHED_TRACER
326 bool "Scheduling Latency Tracer"
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400327 select GENERIC_TRACER
Steven Rostedt352ad252008-05-12 21:20:42 +0200328 select CONTEXT_SWITCH_TRACER
329 select TRACER_MAX_TRACE
Steven Rostedt (Red Hat)22cffc22013-03-05 07:30:24 -0500330 select TRACER_SNAPSHOT
Steven Rostedt352ad252008-05-12 21:20:42 +0200331 help
332 This tracer tracks the latency of the highest priority task
333 to be scheduled in, starting from the point it has woken up.
334
Steven Rostedt (Red Hat)e7c15cd2016-06-23 12:45:36 -0400335config HWLAT_TRACER
336 bool "Tracer to detect hardware latencies (like SMIs)"
337 select GENERIC_TRACER
338 help
339 This tracer, when enabled will create one or more kernel threads,
Jesper Dangaard Brouerc5c1ea72017-06-13 13:06:59 +0200340 depending on what the cpumask file is set to, which each thread
Steven Rostedt (Red Hat)e7c15cd2016-06-23 12:45:36 -0400341 spinning in a loop looking for interruptions caused by
342 something other than the kernel. For example, if a
343 System Management Interrupt (SMI) takes a noticeable amount of
344 time, this tracer will detect it. This is useful for testing
345 if a system is reliable for Real Time tasks.
346
347 Some files are created in the tracing directory when this
348 is enabled:
349
350 hwlat_detector/width - time in usecs for how long to spin for
351 hwlat_detector/window - time in usecs between the start of each
352 iteration
353
354 A kernel thread is created that will spin with interrupts disabled
Jesper Dangaard Brouerc5c1ea72017-06-13 13:06:59 +0200355 for "width" microseconds in every "window" cycle. It will not spin
Steven Rostedt (Red Hat)e7c15cd2016-06-23 12:45:36 -0400356 for "window - width" microseconds, where the system can
357 continue to operate.
358
359 The output will appear in the trace and trace_pipe files.
360
361 When the tracer is not running, it has no affect on the system,
362 but when it is running, it can cause the system to be
363 periodically non responsive. Do not run this tracer on a
364 production system.
365
366 To enable this tracer, echo in "hwlat" into the current_tracer
367 file. Every time a latency is greater than tracing_thresh, it will
368 be recorded into the ring buffer.
369
Daniel Bristot de Oliveirabce29ac2021-06-22 16:42:27 +0200370config OSNOISE_TRACER
371 bool "OS Noise tracer"
372 select GENERIC_TRACER
373 help
374 In the context of high-performance computing (HPC), the Operating
375 System Noise (osnoise) refers to the interference experienced by an
376 application due to activities inside the operating system. In the
377 context of Linux, NMIs, IRQs, SoftIRQs, and any other system thread
378 can cause noise to the system. Moreover, hardware-related jobs can
379 also cause noise, for example, via SMIs.
380
381 The osnoise tracer leverages the hwlat_detector by running a similar
382 loop with preemption, SoftIRQs and IRQs enabled, thus allowing all
383 the sources of osnoise during its execution. The osnoise tracer takes
384 note of the entry and exit point of any source of interferences,
385 increasing a per-cpu interference counter. It saves an interference
386 counter for each source of interference. The interference counter for
387 NMI, IRQs, SoftIRQs, and threads is increased anytime the tool
388 observes these interferences' entry events. When a noise happens
389 without any interference from the operating system level, the
390 hardware noise counter increases, pointing to a hardware-related
391 noise. In this way, osnoise can account for any source of
392 interference. At the end of the period, the osnoise tracer prints
393 the sum of all noise, the max single noise, the percentage of CPU
394 available for the thread, and the counters for the noise sources.
395
396 In addition to the tracer, a set of tracepoints were added to
397 facilitate the identification of the osnoise source.
398
399 The output will appear in the trace and trace_pipe files.
400
401 To enable this tracer, echo in "osnoise" into the current_tracer
402 file.
403
Daniel Bristot de Oliveiraa955d7e2021-06-22 16:42:28 +0200404config TIMERLAT_TRACER
405 bool "Timerlat tracer"
406 select OSNOISE_TRACER
407 select GENERIC_TRACER
408 help
409 The timerlat tracer aims to help the preemptive kernel developers
410 to find sources of wakeup latencies of real-time threads.
411
412 The tracer creates a per-cpu kernel thread with real-time priority.
413 The tracer thread sets a periodic timer to wakeup itself, and goes
414 to sleep waiting for the timer to fire. At the wakeup, the thread
415 then computes a wakeup latency value as the difference between
416 the current time and the absolute time that the timer was set
417 to expire.
418
419 The tracer prints two lines at every activation. The first is the
420 timer latency observed at the hardirq context before the
421 activation of the thread. The second is the timer latency observed
422 by the thread, which is the same level that cyclictest reports. The
423 ACTIVATION ID field serves to relate the irq execution to its
424 respective thread execution.
425
426 The tracer is build on top of osnoise tracer, and the osnoise:
427 events can be used to trace the source of interference from NMI,
428 IRQs and other threads. It also enables the capture of the
429 stacktrace at the IRQ context, which helps to identify the code
430 path that can cause thread delay.
431
Steven Rostedt (VMware)21b3ce32020-01-29 16:26:45 -0500432config MMIOTRACE
433 bool "Memory mapped IO tracing"
434 depends on HAVE_MMIOTRACE_SUPPORT && PCI
435 select GENERIC_TRACER
436 help
437 Mmiotrace traces Memory Mapped I/O access and is meant for
438 debugging and reverse engineering. It is called from the ioremap
439 implementation and works via page faults. Tracing is disabled by
440 default and can be enabled at run-time.
441
442 See Documentation/trace/mmiotrace.rst.
443 If you are not helping to develop drivers, say N.
444
Steven Rostedt897f17a2009-05-28 16:31:21 -0400445config ENABLE_DEFAULT_TRACERS
446 bool "Trace process context switches and events"
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400447 depends on !GENERIC_TRACER
Steven Rostedtb77e38a2009-02-24 10:21:36 -0500448 select TRACING
449 help
Randy Dunlap40892362009-12-21 12:01:17 -0800450 This tracer hooks to various trace points in the kernel,
Steven Rostedtb77e38a2009-02-24 10:21:36 -0500451 allowing the user to pick and choose which trace point they
Steven Rostedt897f17a2009-05-28 16:31:21 -0400452 want to trace. It also includes the sched_switch tracer plugin.
Steven Rostedta7abe972009-04-20 10:59:34 -0400453
Frederic Weisbeckeree08c6e2009-03-07 05:52:59 +0100454config FTRACE_SYSCALLS
455 bool "Trace syscalls"
Josh Stone66700002009-08-24 14:43:11 -0700456 depends on HAVE_SYSCALL_TRACEPOINTS
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400457 select GENERIC_TRACER
Frederic Weisbecker0ea1c412009-03-15 22:10:38 +0100458 select KALLSYMS
Frederic Weisbeckeree08c6e2009-03-07 05:52:59 +0100459 help
460 Basic tracer to catch the syscall entry and exit events.
461
Hiraku Toyookadebdd572012-12-26 11:53:00 +0900462config TRACER_SNAPSHOT
463 bool "Create a snapshot trace buffer"
464 select TRACER_MAX_TRACE
465 help
466 Allow tracing users to take snapshot of the current buffer using the
467 ftrace interface, e.g.:
468
469 echo 1 > /sys/kernel/debug/tracing/snapshot
470 cat snapshot
471
Steven Rostedt (Red Hat)0b85ffc2013-03-05 14:50:23 -0500472config TRACER_SNAPSHOT_PER_CPU_SWAP
Krzysztof Kozlowskifc809bc2019-11-20 21:38:07 +0800473 bool "Allow snapshot to swap per CPU"
Steven Rostedt (Red Hat)0b85ffc2013-03-05 14:50:23 -0500474 depends on TRACER_SNAPSHOT
475 select RING_BUFFER_ALLOW_SWAP
476 help
477 Allow doing a snapshot of a single CPU buffer instead of a
478 full swap (all buffers). If this is set, then the following is
479 allowed:
480
481 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
482
483 After which, only the tracing buffer for CPU 2 was swapped with
484 the main tracing buffer, and the other CPU buffers remain the same.
485
486 When this is enabled, this adds a little more overhead to the
487 trace recording, as it needs to add some checks to synchronize
488 recording with swaps. But this does not affect the performance
489 of the overall system. This is enabled by default when the preempt
490 or irq latency tracers are enabled, as those need to swap as well
491 and already adds the overhead (plus a lot more).
492
Steven Rostedt2ed84ee2008-11-12 15:24:24 -0500493config TRACE_BRANCH_PROFILING
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400494 bool
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400495 select GENERIC_TRACER
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400496
497choice
498 prompt "Branch Profiling"
499 default BRANCH_PROFILE_NONE
500 help
501 The branch profiling is a software profiler. It will add hooks
502 into the C conditionals to test which path a branch takes.
503
504 The likely/unlikely profiler only looks at the conditions that
505 are annotated with a likely or unlikely macro.
506
Randy Dunlap40892362009-12-21 12:01:17 -0800507 The "all branch" profiler will profile every if-statement in the
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400508 kernel. This profiler will also enable the likely/unlikely
Randy Dunlap40892362009-12-21 12:01:17 -0800509 profiler.
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400510
Randy Dunlap40892362009-12-21 12:01:17 -0800511 Either of the above profilers adds a bit of overhead to the system.
512 If unsure, choose "No branch profiling".
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400513
514config BRANCH_PROFILE_NONE
515 bool "No branch profiling"
516 help
Randy Dunlap40892362009-12-21 12:01:17 -0800517 No branch profiling. Branch profiling adds a bit of overhead.
518 Only enable it if you want to analyse the branching behavior.
519 Otherwise keep it disabled.
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400520
521config PROFILE_ANNOTATED_BRANCHES
522 bool "Trace likely/unlikely profiler"
523 select TRACE_BRANCH_PROFILING
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500524 help
Masanari Iida59bf8962012-04-18 00:01:21 +0900525 This tracer profiles all likely and unlikely macros
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500526 in the kernel. It will display the results in:
527
David Rientjes13e5bef2011-03-16 17:17:08 -0700528 /sys/kernel/debug/tracing/trace_stat/branch_annotated
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500529
Randy Dunlap40892362009-12-21 12:01:17 -0800530 Note: this will add a significant overhead; only turn this
Steven Rostedt1f0d69a2008-11-12 00:14:39 -0500531 on if you need to profile the system's use of these macros.
532
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500533config PROFILE_ALL_BRANCHES
Randy Dunlap68e76e02018-01-15 11:07:27 -0800534 bool "Profile all if conditionals" if !FORTIFY_SOURCE
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400535 select TRACE_BRANCH_PROFILING
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500536 help
537 This tracer profiles all branch conditions. Every if ()
538 taken in the kernel is recorded whether it hit or miss.
539 The results will be displayed in:
540
David Rientjes13e5bef2011-03-16 17:17:08 -0700541 /sys/kernel/debug/tracing/trace_stat/branch_all
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500542
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400543 This option also enables the likely/unlikely profiler.
544
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500545 This configuration, when enabled, will impose a great overhead
546 on the system. This should only be enabled when the system
Randy Dunlap40892362009-12-21 12:01:17 -0800547 is to be analyzed in much detail.
Steven Rostedt9ae5b872009-04-20 10:27:58 -0400548endchoice
Steven Rostedt2bcd5212008-11-21 01:30:54 -0500549
Steven Rostedt2ed84ee2008-11-12 15:24:24 -0500550config TRACING_BRANCHES
Steven Rostedt52f232c2008-11-12 00:14:40 -0500551 bool
552 help
553 Selected by tracers that will trace the likely and unlikely
554 conditions. This prevents the tracers themselves from being
555 profiled. Profiling the tracing infrastructure can only happen
556 when the likelys and unlikelys are not being traced.
557
Steven Rostedt2ed84ee2008-11-12 15:24:24 -0500558config BRANCH_TRACER
Steven Rostedt52f232c2008-11-12 00:14:40 -0500559 bool "Trace likely/unlikely instances"
Steven Rostedt2ed84ee2008-11-12 15:24:24 -0500560 depends on TRACE_BRANCH_PROFILING
561 select TRACING_BRANCHES
Steven Rostedt52f232c2008-11-12 00:14:40 -0500562 help
563 This traces the events of likely and unlikely condition
564 calls in the kernel. The difference between this and the
565 "Trace likely/unlikely profiler" is that this is not a
566 histogram of the callers, but actually places the calling
567 events into a running trace buffer to see when and where the
568 events happened, as well as their results.
569
570 Say N if unsure.
571
Frederic Weisbecker2db270a2009-02-07 20:46:45 +0100572config BLK_DEV_IO_TRACE
Randy Dunlap40892362009-12-21 12:01:17 -0800573 bool "Support for tracing block IO actions"
Frederic Weisbecker2db270a2009-02-07 20:46:45 +0100574 depends on SYSFS
Ingo Molnar1dfba052009-02-09 12:06:54 +0100575 depends on BLOCK
Frederic Weisbecker2db270a2009-02-07 20:46:45 +0100576 select RELAY
577 select DEBUG_FS
578 select TRACEPOINTS
Steven Rostedt5e0a0932009-05-28 15:50:13 -0400579 select GENERIC_TRACER
Frederic Weisbecker2db270a2009-02-07 20:46:45 +0100580 select STACKTRACE
581 help
582 Say Y here if you want to be able to trace the block layer actions
583 on a given queue. Tracing allows you to see any traffic happening
584 on a block device queue. For more information (and the userspace
585 support tools needed), fetch the blktrace tools from:
586
587 git://git.kernel.dk/blktrace.git
588
589 Tracing also is possible using the ftrace interface, e.g.:
590
591 echo 1 > /sys/block/sda/sda1/trace/enable
592 echo blk > /sys/kernel/debug/tracing/current_tracer
593 cat /sys/kernel/debug/tracing/trace_pipe
594
595 If unsure, say N.
Frederic Weisbecker36994e52008-12-29 13:42:23 -0800596
Anton Blanchard6b0b7552017-02-16 17:00:50 +1100597config KPROBE_EVENTS
Masami Hiramatsu413d37d2009-08-13 16:35:11 -0400598 depends on KPROBES
Heiko Carstensf850c30c2010-02-10 17:25:17 +0100599 depends on HAVE_REGS_AND_STACK_ACCESS_API
Masami Hiramatsu77b44d12009-11-03 19:12:47 -0500600 bool "Enable kprobes-based dynamic events"
Masami Hiramatsu413d37d2009-08-13 16:35:11 -0400601 select TRACING
Srikar Dronamraju8ab83f52012-04-09 14:41:44 +0530602 select PROBE_EVENTS
Masami Hiramatsu6212dd22018-11-05 18:02:36 +0900603 select DYNAMIC_EVENTS
Masami Hiramatsu77b44d12009-11-03 19:12:47 -0500604 default y
Masami Hiramatsu413d37d2009-08-13 16:35:11 -0400605 help
Randy Dunlap40892362009-12-21 12:01:17 -0800606 This allows the user to add tracing events (similar to tracepoints)
607 on the fly via the ftrace interface. See
Mauro Carvalho Chehab5fb94e92018-05-08 15:14:57 -0300608 Documentation/trace/kprobetrace.rst for more details.
Masami Hiramatsu77b44d12009-11-03 19:12:47 -0500609
610 Those events can be inserted wherever kprobes can probe, and record
611 various register and memory values.
612
Randy Dunlap40892362009-12-21 12:01:17 -0800613 This option is also required by perf-probe subcommand of perf tools.
614 If you want to use perf tools, this option is strongly recommended.
Masami Hiramatsu413d37d2009-08-13 16:35:11 -0400615
Masami Hiramatsu45408c42018-07-30 19:20:14 +0900616config KPROBE_EVENTS_ON_NOTRACE
617 bool "Do NOT protect notrace function from kprobe events"
618 depends on KPROBE_EVENTS
Masami Hiramatsu7bb83f6f2021-01-08 13:19:38 +0900619 depends on DYNAMIC_FTRACE
Masami Hiramatsu45408c42018-07-30 19:20:14 +0900620 default n
621 help
622 This is only for the developers who want to debug ftrace itself
623 using kprobe events.
624
625 If kprobes can use ftrace instead of breakpoint, ftrace related
Colin Ian King28cc65a2020-12-16 11:40:51 +0000626 functions are protected from kprobe-events to prevent an infinite
Masami Hiramatsu45408c42018-07-30 19:20:14 +0900627 recursion or any unexpected execution path which leads to a kernel
628 crash.
629
630 This option disables such protection and allows you to put kprobe
631 events on ftrace functions for debugging ftrace by itself.
632 Note that this might let you shoot yourself in the foot.
633
634 If unsure, say N.
635
Anton Blanchard6b0b7552017-02-16 17:00:50 +1100636config UPROBE_EVENTS
Srikar Dronamrajuf3f096c2012-04-11 16:00:43 +0530637 bool "Enable uprobes-based dynamic events"
638 depends on ARCH_SUPPORTS_UPROBES
639 depends on MMU
David A. Long09294e32014-03-07 10:32:22 -0500640 depends on PERF_EVENTS
Srikar Dronamrajuf3f096c2012-04-11 16:00:43 +0530641 select UPROBES
642 select PROBE_EVENTS
Masami Hiramatsu0597c492018-11-05 18:03:04 +0900643 select DYNAMIC_EVENTS
Srikar Dronamrajuf3f096c2012-04-11 16:00:43 +0530644 select TRACING
Arnaldo Carvalho de Melo61f35d72017-03-16 12:42:02 -0300645 default y
Srikar Dronamrajuf3f096c2012-04-11 16:00:43 +0530646 help
647 This allows the user to add tracing events on top of userspace
648 dynamic events (similar to tracepoints) on the fly via the trace
649 events interface. Those events can be inserted wherever uprobes
650 can probe, and record various registers.
651 This option is required if you plan to use perf-probe subcommand
652 of perf tools on user space applications.
653
Ingo Molnare1abf2c2015-04-02 15:51:39 +0200654config BPF_EVENTS
655 depends on BPF_SYSCALL
Anton Blanchard6b0b7552017-02-16 17:00:50 +1100656 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
Ingo Molnare1abf2c2015-04-02 15:51:39 +0200657 bool
658 default y
659 help
Peter Wu5cbd22c2019-08-21 00:08:57 +0100660 This allows the user to attach BPF programs to kprobe, uprobe, and
661 tracepoint events.
Ingo Molnare1abf2c2015-04-02 15:51:39 +0200662
Masami Hiramatsu5448d442018-11-05 18:02:08 +0900663config DYNAMIC_EVENTS
664 def_bool n
665
Srikar Dronamraju8ab83f52012-04-09 14:41:44 +0530666config PROBE_EVENTS
667 def_bool n
668
Josef Bacik9802d862017-12-11 11:36:48 -0500669config BPF_KPROBE_OVERRIDE
670 bool "Enable BPF programs to override a kprobed function"
671 depends on BPF_EVENTS
Masami Hiramatsu540adea2018-01-13 02:55:03 +0900672 depends on FUNCTION_ERROR_INJECTION
Josef Bacik9802d862017-12-11 11:36:48 -0500673 default n
674 help
675 Allows BPF to override the execution of a probed function and
676 set a different return value. This is used for error injection.
677
Steven Rostedt8da38212008-08-14 15:45:07 -0400678config FTRACE_MCOUNT_RECORD
679 def_bool y
680 depends on DYNAMIC_FTRACE
681 depends on HAVE_FTRACE_MCOUNT_RECORD
682
Sami Tolvanen3b15cdc12020-12-11 10:46:18 -0800683config FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
684 bool
685 depends on FTRACE_MCOUNT_RECORD
686
687config FTRACE_MCOUNT_USE_CC
688 def_bool y
689 depends on $(cc-option,-mrecord-mcount)
690 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
691 depends on FTRACE_MCOUNT_RECORD
692
Sami Tolvanen22c85422020-09-25 16:43:53 -0700693config FTRACE_MCOUNT_USE_OBJTOOL
694 def_bool y
695 depends on HAVE_OBJTOOL_MCOUNT
696 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
697 depends on !FTRACE_MCOUNT_USE_CC
698 depends on FTRACE_MCOUNT_RECORD
699
Sami Tolvanen3b15cdc12020-12-11 10:46:18 -0800700config FTRACE_MCOUNT_USE_RECORDMCOUNT
701 def_bool y
702 depends on !FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY
703 depends on !FTRACE_MCOUNT_USE_CC
Sami Tolvanen22c85422020-09-25 16:43:53 -0700704 depends on !FTRACE_MCOUNT_USE_OBJTOOL
Sami Tolvanen3b15cdc12020-12-11 10:46:18 -0800705 depends on FTRACE_MCOUNT_RECORD
706
Tom Zanussi08d43a52015-12-10 12:50:50 -0600707config TRACING_MAP
708 bool
709 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
Tom Zanussi08d43a52015-12-10 12:50:50 -0600710 help
711 tracing_map is a special-purpose lock-free map for tracing,
712 separated out as a stand-alone facility in order to allow it
713 to be shared between multiple tracers. It isn't meant to be
714 generally used outside of that context, and is normally
715 selected by tracers that use it.
716
Tom Zanussi726721a2020-05-28 14:32:37 -0500717config SYNTH_EVENTS
718 bool "Synthetic trace events"
719 select TRACING
720 select DYNAMIC_EVENTS
721 default n
722 help
723 Synthetic events are user-defined trace events that can be
724 used to combine data from other trace events or in fact any
725 data source. Synthetic events can be generated indirectly
726 via the trace() action of histogram triggers or directly
727 by way of an in-kernel API.
728
729 See Documentation/trace/events.rst or
730 Documentation/trace/histogram.rst for details and examples.
731
732 If in doubt, say N.
733
Tom Zanussi7ef224d2016-03-03 12:54:42 -0600734config HIST_TRIGGERS
735 bool "Histogram triggers"
736 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
737 select TRACING_MAP
Tom Zanussi7ad8fb62016-07-03 08:51:34 -0500738 select TRACING
Masami Hiramatsu7bbab382018-11-05 18:03:33 +0900739 select DYNAMIC_EVENTS
Tom Zanussi726721a2020-05-28 14:32:37 -0500740 select SYNTH_EVENTS
Tom Zanussi7ef224d2016-03-03 12:54:42 -0600741 default n
742 help
743 Hist triggers allow one or more arbitrary trace event fields
744 to be aggregated into hash tables and dumped to stdout by
745 reading a debugfs/tracefs file. They're useful for
746 gathering quick and dirty (though precise) summaries of
747 event activity as an initial guide for further investigation
748 using more advanced tools.
749
Tom Zanussi89e270c2018-01-15 20:52:10 -0600750 Inter-event tracing of quantities such as latencies is also
751 supported using hist triggers under this option.
752
Mauro Carvalho Chehabea272252018-06-26 06:49:11 -0300753 See Documentation/trace/histogram.rst.
Tom Zanussi7ef224d2016-03-03 12:54:42 -0600754 If in doubt, say N.
755
Cong Wang6c3edaf2019-11-29 20:52:18 -0800756config TRACE_EVENT_INJECT
757 bool "Trace event injection"
758 depends on TRACING
759 help
760 Allow user-space to inject a specific trace event into the ring
761 buffer. This is mainly used for testing purpose.
762
763 If unsure, say N.
764
Steven Rostedt (Red Hat)81dc9f02014-05-29 22:49:07 -0400765config TRACEPOINT_BENCHMARK
Krzysztof Kozlowskifc809bc2019-11-20 21:38:07 +0800766 bool "Add tracepoint that benchmarks tracepoints"
Steven Rostedt (Red Hat)81dc9f02014-05-29 22:49:07 -0400767 help
768 This option creates the tracepoint "benchmark:benchmark_event".
769 When the tracepoint is enabled, it kicks off a kernel thread that
Rolf Eike Beer69268092021-03-02 09:49:28 +0100770 goes into an infinite loop (calling cond_resched() to let other tasks
Steven Rostedt (Red Hat)81dc9f02014-05-29 22:49:07 -0400771 run), and calls the tracepoint. Each iteration will record the time
772 it took to write to the tracepoint and the next iteration that
773 data will be passed to the tracepoint itself. That is, the tracepoint
774 will report the time it took to do the previous tracepoint.
775 The string written to the tracepoint is a static string of 128 bytes
776 to keep the time the same. The initial string is simply a write of
777 "START". The second string records the cold cache time of the first
778 write which is not added to the rest of the calculations.
779
780 As it is a tight loop, it benchmarks as hot cache. That's fine because
781 we care most about hot paths that are probably in cache already.
782
783 An example of the output:
784
785 START
786 first=3672 [COLD CACHED]
787 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
788 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
789 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
790 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
791 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
792 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
793
794
Steven Rostedt5092dbc2009-05-05 22:47:18 -0400795config RING_BUFFER_BENCHMARK
796 tristate "Ring buffer benchmark stress tester"
797 depends on RING_BUFFER
798 help
Randy Dunlap40892362009-12-21 12:01:17 -0800799 This option creates a test to stress the ring buffer and benchmark it.
800 It creates its own ring buffer such that it will not interfere with
Steven Rostedt5092dbc2009-05-05 22:47:18 -0400801 any other users of the ring buffer (such as ftrace). It then creates
802 a producer and consumer that will run for 10 seconds and sleep for
803 10 seconds. Each interval it will print out the number of events
804 it recorded and give a rough estimate of how long each iteration took.
805
806 It does not disable interrupts or raise its priority, so it may be
807 affected by processes that are running.
808
Randy Dunlap40892362009-12-21 12:01:17 -0800809 If unsure, say N.
Steven Rostedt5092dbc2009-05-05 22:47:18 -0400810
Steven Rostedt (VMware)1e837942020-01-29 16:30:30 -0500811config TRACE_EVAL_MAP_FILE
812 bool "Show eval mappings for trace events"
813 depends on TRACING
814 help
815 The "print fmt" of the trace events will show the enum/sizeof names
816 instead of their values. This can cause problems for user space tools
817 that use this string to parse the raw data as user space does not know
818 how to convert the string to its value.
819
820 To fix this, there's a special macro in the kernel that can be used
821 to convert an enum/sizeof into its value. If this macro is used, then
822 the print fmt strings will be converted to their values.
823
824 If something does not get converted properly, this option can be
825 used to show what enums/sizeof the kernel tried to convert.
826
827 This option is for debugging the conversions. A file is created
828 in the tracing directory called "eval_map" that will show the
829 names matched with their values and what trace event system they
830 belong too.
831
832 Normally, the mapping of the strings to values will be freed after
833 boot up or module load. With this option, they will not be freed, as
834 they are needed for the "eval_map" file. Enabling this option will
835 increase the memory footprint of the running kernel.
836
837 If unsure, say N.
838
Steven Rostedt (VMware)773c1672020-11-05 21:32:46 -0500839config FTRACE_RECORD_RECURSION
840 bool "Record functions that recurse in function tracing"
841 depends on FUNCTION_TRACER
842 help
843 All callbacks that attach to the function tracing have some sort
844 of protection against recursion. Even though the protection exists,
845 it adds overhead. This option will create a file in the tracefs
846 file system called "recursed_functions" that will list the functions
847 that triggered a recursion.
848
849 This will add more overhead to cases that have recursion.
850
851 If unsure, say N
852
853config FTRACE_RECORD_RECURSION_SIZE
854 int "Max number of recursed functions to record"
855 default 128
856 depends on FTRACE_RECORD_RECURSION
857 help
858 This defines the limit of number of functions that can be
859 listed in the "recursed_functions" file, that lists all
860 the functions that caused a recursion to happen.
861 This file can be reset, but the limit can not change in
862 size at runtime.
863
Steven Rostedt (VMware)28575c62020-11-02 14:43:10 -0500864config RING_BUFFER_RECORD_RECURSION
865 bool "Record functions that recurse in the ring buffer"
866 depends on FTRACE_RECORD_RECURSION
867 # default y, because it is coupled with FTRACE_RECORD_RECURSION
868 default y
869 help
870 The ring buffer has its own internal recursion. Although when
871 recursion happens it wont cause harm because of the protection,
872 but it does cause an unwanted overhead. Enabling this option will
873 place where recursion was detected into the ftrace "recursed_functions"
874 file.
875
876 This will add more overhead to cases that have recursion.
877
Steven Rostedt (VMware)1e837942020-01-29 16:30:30 -0500878config GCOV_PROFILE_FTRACE
879 bool "Enable GCOV profiling on ftrace subsystem"
880 depends on GCOV_KERNEL
881 help
882 Enable GCOV profiling on ftrace subsystem for checking
883 which functions/lines are tested.
884
885 If unsure, say N.
886
887 Note that on a kernel compiled with this config, ftrace will
888 run significantly slower.
889
890config FTRACE_SELFTEST
891 bool
892
893config FTRACE_STARTUP_TEST
894 bool "Perform a startup test on ftrace"
895 depends on GENERIC_TRACER
896 select FTRACE_SELFTEST
897 help
898 This option performs a series of startup tests on ftrace. On bootup
899 a series of tests are made to verify that the tracer is
900 functioning properly. It will do tests on all the configured
901 tracers of ftrace.
902
903config EVENT_TRACE_STARTUP_TEST
904 bool "Run selftest on trace events"
905 depends on FTRACE_STARTUP_TEST
906 default y
907 help
908 This option performs a test on all trace events in the system.
909 It basically just enables each event and runs some code that
910 will trigger events (not necessarily the event it enables)
911 This may take some time run as there are a lot of events.
912
913config EVENT_TRACE_TEST_SYSCALLS
914 bool "Run selftest on syscall events"
915 depends on EVENT_TRACE_STARTUP_TEST
916 help
917 This option will also enable testing every syscall event.
918 It only enables the event and disables it and runs various loads
919 with the event enabled. This adds a bit more time for kernel boot
920 up since it runs this on every system call defined.
921
922 TBD - enable a way to actually call the syscalls as we test their
923 events
924
Steven Rostedt (VMware)8147dc782021-12-06 15:18:58 -0500925config FTRACE_SORT_STARTUP_TEST
926 bool "Verify compile time sorting of ftrace functions"
927 depends on DYNAMIC_FTRACE
Steven Rostedt (Google)6b9b6412022-01-22 09:17:10 -0500928 depends on BUILDTIME_MCOUNT_SORT
Steven Rostedt (VMware)8147dc782021-12-06 15:18:58 -0500929 help
930 Sorting of the mcount_loc sections that is used to find the
931 where the ftrace knows where to patch functions for tracing
932 and other callbacks is done at compile time. But if the sort
933 is not done correctly, it will cause non-deterministic failures.
934 When this is set, the sorted sections will be verified that they
935 are in deed sorted and will warn if they are not.
936
937 If unsure, say N
938
Steven Rostedt (Red Hat)6c43e552013-03-15 11:32:53 -0400939config RING_BUFFER_STARTUP_TEST
940 bool "Ring buffer startup self test"
941 depends on RING_BUFFER
942 help
Krzysztof Kozlowskifc809bc2019-11-20 21:38:07 +0800943 Run a simple self test on the ring buffer on boot up. Late in the
Steven Rostedt (Red Hat)6c43e552013-03-15 11:32:53 -0400944 kernel boot sequence, the test will start that kicks off
945 a thread per cpu. Each thread will write various size events
946 into the ring buffer. Another thread is created to send IPIs
947 to each of the threads, where the IPI handler will also write
948 to the ring buffer, to test/stress the nesting ability.
949 If any anomalies are discovered, a warning will be displayed
950 and all ring buffers will be disabled.
951
952 The test runs for 10 seconds. This will slow your boot time
953 by at least 10 more seconds.
954
955 At the end of the test, statics and more checks are done.
956 It will output the stats of each per cpu buffer. What
957 was written, the sizes, what was read, what was lost, and
958 other similar details.
959
960 If unsure, say N
961
Steven Rostedt (VMware)5b7be9c2020-11-30 23:37:33 -0500962config RING_BUFFER_VALIDATE_TIME_DELTAS
963 bool "Verify ring buffer time stamp deltas"
964 depends on RING_BUFFER
965 help
966 This will audit the time stamps on the ring buffer sub
967 buffer to make sure that all the time deltas for the
968 events on a sub buffer matches the current time stamp.
969 This audit is performed for every event that is not
970 interrupted, or interrupting another event. A check
971 is also made when traversing sub buffers to make sure
972 that all the deltas on the previous sub buffer do not
973 add up to be greater than the current time stamp.
974
975 NOTE: This adds significant overhead to recording of events,
976 and should only be used to test the logic of the ring buffer.
977 Do not use it on production systems.
978
979 Only say Y if you understand what this does, and you
980 still want it enabled. Otherwise say N
981
Steven Rostedt (VMware)a48fc4f2020-01-29 16:23:04 -0500982config MMIOTRACE_TEST
983 tristate "Test module for mmiotrace"
984 depends on MMIOTRACE && m
985 help
986 This is a dumb module for testing mmiotrace. It is very dangerous
987 as it will write garbage to IO memory starting at a given address.
988 However, it should be safe to use on e.g. unused portion of VRAM.
989
990 Say N, unless you absolutely know what you are doing.
991
Joel Fernandes (Google)f96e8572018-07-12 14:36:11 -0700992config PREEMPTIRQ_DELAY_TEST
Steven Rostedt (VMware)a48fc4f2020-01-29 16:23:04 -0500993 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
Joel Fernandes (Google)f96e8572018-07-12 14:36:11 -0700994 depends on m
995 help
996 Select this option to build a test module that can help test latency
997 tracers by executing a preempt or irq disable section with a user
998 configurable delay. The module busy waits for the duration of the
999 critical section.
1000
Viktor Rosendahl (BMW)79393722019-10-09 00:08:22 +02001001 For example, the following invocation generates a burst of three
1002 irq-disabled critical sections for 500us:
1003 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
Joel Fernandes (Google)f96e8572018-07-12 14:36:11 -07001004
Song Chen4b9091e2021-01-28 09:35:13 +08001005 What's more, if you want to attach the test on the cpu which the latency
1006 tracer is running on, specify cpu_affinity=cpu_num at the end of the
1007 command.
1008
Joel Fernandes (Google)f96e8572018-07-12 14:36:11 -07001009 If unsure, say N
1010
Tom Zanussi9fe41ef2020-01-29 12:59:28 -06001011config SYNTH_EVENT_GEN_TEST
1012 tristate "Test module for in-kernel synthetic event generation"
Tom Zanussi726721a2020-05-28 14:32:37 -05001013 depends on SYNTH_EVENTS
Tom Zanussi9fe41ef2020-01-29 12:59:28 -06001014 help
1015 This option creates a test module to check the base
1016 functionality of in-kernel synthetic event definition and
1017 generation.
1018
1019 To test, insert the module, and then check the trace buffer
1020 for the generated sample events.
1021
1022 If unsure, say N.
1023
Tom Zanussi64836242020-01-29 12:59:31 -06001024config KPROBE_EVENT_GEN_TEST
1025 tristate "Test module for in-kernel kprobe event generation"
1026 depends on KPROBE_EVENTS
1027 help
1028 This option creates a test module to check the base
1029 functionality of in-kernel kprobe event definition.
1030
1031 To test, insert the module, and then check the trace buffer
1032 for the generated kprobe events.
1033
1034 If unsure, say N.
1035
Tom Zanussi2d19bd72020-04-03 14:31:21 -05001036config HIST_TRIGGERS_DEBUG
1037 bool "Hist trigger debug support"
1038 depends on HIST_TRIGGERS
1039 help
1040 Add "hist_debug" file for each event, which when read will
1041 dump out a bunch of internal details about the hist triggers
1042 defined on that event.
1043
1044 The hist_debug file serves a couple of purposes:
1045
1046 - Helps developers verify that nothing is broken.
1047
1048 - Provides educational information to support the details
1049 of the hist trigger internals as described by
1050 Documentation/trace/histogram-design.rst.
1051
1052 The hist_debug output only covers the data structures
1053 related to the histogram definitions themselves and doesn't
1054 display the internals of map buckets or variable values of
1055 running histograms.
1056
1057 If unsure, say N.
1058
Steven Rostedt4ed9f072009-04-20 10:47:36 -04001059endif # FTRACE