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1#
2# Architectures that offer an FUNCTION_TRACER implementation should
3# select HAVE_FUNCTION_TRACER:
4#
5
6config USER_STACKTRACE_SUPPORT
7 bool
8
9config NOP_TRACER
10 bool
11
12config HAVE_FTRACE_NMI_ENTER
13 bool
14 help
15 See Documentation/trace/ftrace-design.txt
16
17config HAVE_FUNCTION_TRACER
18 bool
19 help
20 See Documentation/trace/ftrace-design.txt
21
22config HAVE_FUNCTION_GRAPH_TRACER
23 bool
24 help
25 See Documentation/trace/ftrace-design.txt
26
27config HAVE_DYNAMIC_FTRACE
28 bool
29 help
30 See Documentation/trace/ftrace-design.txt
31
32config HAVE_DYNAMIC_FTRACE_WITH_REGS
33 bool
34
35config HAVE_FTRACE_MCOUNT_RECORD
36 bool
37 help
38 See Documentation/trace/ftrace-design.txt
39
40config HAVE_SYSCALL_TRACEPOINTS
41 bool
42 help
43 See Documentation/trace/ftrace-design.txt
44
45config HAVE_FENTRY
46 bool
47 help
48 Arch supports the gcc options -pg with -mfentry
49
50config HAVE_C_RECORDMCOUNT
51 bool
52 help
53 C version of recordmcount available?
54
55config TRACER_MAX_TRACE
56 bool
57
58config TRACE_CLOCK
59 bool
60
61config RING_BUFFER
62 bool
63 select TRACE_CLOCK
64 select IRQ_WORK
65
66config FTRACE_NMI_ENTER
67 bool
68 depends on HAVE_FTRACE_NMI_ENTER
69 default y
70
71config EVENT_TRACING
72 select CONTEXT_SWITCH_TRACER
73 select GLOB
74 bool
75
76config CONTEXT_SWITCH_TRACER
77 bool
78
79config RING_BUFFER_ALLOW_SWAP
80 bool
81 help
82 Allow the use of ring_buffer_swap_cpu.
83 Adds a very slight overhead to tracing when enabled.
84
85# All tracer options should select GENERIC_TRACER. For those options that are
86# enabled by all tracers (context switch and event tracer) they select TRACING.
87# This allows those options to appear when no other tracer is selected. But the
88# options do not appear when something else selects it. We need the two options
89# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
90# hiding of the automatic options.
91
92config TRACING
93 bool
94 select DEBUG_FS
95 select RING_BUFFER
96 select STACKTRACE if STACKTRACE_SUPPORT
97 select TRACEPOINTS
98 select NOP_TRACER
99 select BINARY_PRINTF
100 select EVENT_TRACING
101 select TRACE_CLOCK
102
103config GENERIC_TRACER
104 bool
105 select TRACING
106
107#
108# Minimum requirements an architecture has to meet for us to
109# be able to offer generic tracing facilities:
110#
111config TRACING_SUPPORT
112 bool
113 # PPC32 has no irqflags tracing support, but it can use most of the
114 # tracers anyway, they were tested to build and work. Note that new
115 # exceptions to this list aren't welcomed, better implement the
116 # irqflags tracing for your architecture.
117 depends on TRACE_IRQFLAGS_SUPPORT || PPC32
118 depends on STACKTRACE_SUPPORT
119 default y
120
121if TRACING_SUPPORT
122
123menuconfig FTRACE
124 bool "Tracers"
125 default y if DEBUG_KERNEL
126 help
127 Enable the kernel tracing infrastructure.
128
129if FTRACE
130
131config FUNCTION_TRACER
132 bool "Kernel Function Tracer"
133 depends on HAVE_FUNCTION_TRACER
134 select KALLSYMS
135 select GENERIC_TRACER
136 select CONTEXT_SWITCH_TRACER
137 select GLOB
138 help
139 Enable the kernel to trace every kernel function. This is done
140 by using a compiler feature to insert a small, 5-byte No-Operation
141 instruction at the beginning of every kernel function, which NOP
142 sequence is then dynamically patched into a tracer call when
143 tracing is enabled by the administrator. If it's runtime disabled
144 (the bootup default), then the overhead of the instructions is very
145 small and not measurable even in micro-benchmarks.
146
147config FUNCTION_GRAPH_TRACER
148 bool "Kernel Function Graph Tracer"
149 depends on HAVE_FUNCTION_GRAPH_TRACER
150 depends on FUNCTION_TRACER
151 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
152 default y
153 help
154 Enable the kernel to trace a function at both its return
155 and its entry.
156 Its first purpose is to trace the duration of functions and
157 draw a call graph for each thread with some information like
158 the return value. This is done by setting the current return
159 address on the current task structure into a stack of calls.
160
161
162config IRQSOFF_TRACER
163 bool "Interrupts-off Latency Tracer"
164 default n
165 depends on TRACE_IRQFLAGS_SUPPORT
166 depends on !ARCH_USES_GETTIMEOFFSET
167 select TRACE_IRQFLAGS
168 select GENERIC_TRACER
169 select TRACER_MAX_TRACE
170 select RING_BUFFER_ALLOW_SWAP
171 select TRACER_SNAPSHOT
172 select TRACER_SNAPSHOT_PER_CPU_SWAP
173 help
174 This option measures the time spent in irqs-off critical
175 sections, with microsecond accuracy.
176
177 The default measurement method is a maximum search, which is
178 disabled by default and can be runtime (re-)started
179 via:
180
181 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
182
183 (Note that kernel size and overhead increase with this option
184 enabled. This option and the preempt-off timing option can be
185 used together or separately.)
186
187config PREEMPT_TRACER
188 bool "Preemption-off Latency Tracer"
189 default n
190 depends on !ARCH_USES_GETTIMEOFFSET
191 depends on PREEMPT
192 select GENERIC_TRACER
193 select TRACER_MAX_TRACE
194 select RING_BUFFER_ALLOW_SWAP
195 select TRACER_SNAPSHOT
196 select TRACER_SNAPSHOT_PER_CPU_SWAP
197 help
198 This option measures the time spent in preemption-off critical
199 sections, with microsecond accuracy.
200
201 The default measurement method is a maximum search, which is
202 disabled by default and can be runtime (re-)started
203 via:
204
205 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
206
207 (Note that kernel size and overhead increase with this option
208 enabled. This option and the irqs-off timing option can be
209 used together or separately.)
210
211config SCHED_TRACER
212 bool "Scheduling Latency Tracer"
213 select GENERIC_TRACER
214 select CONTEXT_SWITCH_TRACER
215 select TRACER_MAX_TRACE
216 select TRACER_SNAPSHOT
217 help
218 This tracer tracks the latency of the highest priority task
219 to be scheduled in, starting from the point it has woken up.
220
221config HWLAT_TRACER
222 bool "Tracer to detect hardware latencies (like SMIs)"
223 select GENERIC_TRACER
224 help
225 This tracer, when enabled will create one or more kernel threads,
226 depening on what the cpumask file is set to, which each thread
227 spinning in a loop looking for interruptions caused by
228 something other than the kernel. For example, if a
229 System Management Interrupt (SMI) takes a noticeable amount of
230 time, this tracer will detect it. This is useful for testing
231 if a system is reliable for Real Time tasks.
232
233 Some files are created in the tracing directory when this
234 is enabled:
235
236 hwlat_detector/width - time in usecs for how long to spin for
237 hwlat_detector/window - time in usecs between the start of each
238 iteration
239
240 A kernel thread is created that will spin with interrupts disabled
241 for "width" microseconds in every "widow" cycle. It will not spin
242 for "window - width" microseconds, where the system can
243 continue to operate.
244
245 The output will appear in the trace and trace_pipe files.
246
247 When the tracer is not running, it has no affect on the system,
248 but when it is running, it can cause the system to be
249 periodically non responsive. Do not run this tracer on a
250 production system.
251
252 To enable this tracer, echo in "hwlat" into the current_tracer
253 file. Every time a latency is greater than tracing_thresh, it will
254 be recorded into the ring buffer.
255
256config ENABLE_DEFAULT_TRACERS
257 bool "Trace process context switches and events"
258 depends on !GENERIC_TRACER
259 select TRACING
260 help
261 This tracer hooks to various trace points in the kernel,
262 allowing the user to pick and choose which trace point they
263 want to trace. It also includes the sched_switch tracer plugin.
264
265config FTRACE_SYSCALLS
266 bool "Trace syscalls"
267 depends on HAVE_SYSCALL_TRACEPOINTS
268 select GENERIC_TRACER
269 select KALLSYMS
270 help
271 Basic tracer to catch the syscall entry and exit events.
272
273config TRACER_SNAPSHOT
274 bool "Create a snapshot trace buffer"
275 select TRACER_MAX_TRACE
276 help
277 Allow tracing users to take snapshot of the current buffer using the
278 ftrace interface, e.g.:
279
280 echo 1 > /sys/kernel/debug/tracing/snapshot
281 cat snapshot
282
283config TRACER_SNAPSHOT_PER_CPU_SWAP
284 bool "Allow snapshot to swap per CPU"
285 depends on TRACER_SNAPSHOT
286 select RING_BUFFER_ALLOW_SWAP
287 help
288 Allow doing a snapshot of a single CPU buffer instead of a
289 full swap (all buffers). If this is set, then the following is
290 allowed:
291
292 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
293
294 After which, only the tracing buffer for CPU 2 was swapped with
295 the main tracing buffer, and the other CPU buffers remain the same.
296
297 When this is enabled, this adds a little more overhead to the
298 trace recording, as it needs to add some checks to synchronize
299 recording with swaps. But this does not affect the performance
300 of the overall system. This is enabled by default when the preempt
301 or irq latency tracers are enabled, as those need to swap as well
302 and already adds the overhead (plus a lot more).
303
304config TRACE_BRANCH_PROFILING
305 bool
306 select GENERIC_TRACER
307
308choice
309 prompt "Branch Profiling"
310 default BRANCH_PROFILE_NONE
311 help
312 The branch profiling is a software profiler. It will add hooks
313 into the C conditionals to test which path a branch takes.
314
315 The likely/unlikely profiler only looks at the conditions that
316 are annotated with a likely or unlikely macro.
317
318 The "all branch" profiler will profile every if-statement in the
319 kernel. This profiler will also enable the likely/unlikely
320 profiler.
321
322 Either of the above profilers adds a bit of overhead to the system.
323 If unsure, choose "No branch profiling".
324
325config BRANCH_PROFILE_NONE
326 bool "No branch profiling"
327 help
328 No branch profiling. Branch profiling adds a bit of overhead.
329 Only enable it if you want to analyse the branching behavior.
330 Otherwise keep it disabled.
331
332config PROFILE_ANNOTATED_BRANCHES
333 bool "Trace likely/unlikely profiler"
334 select TRACE_BRANCH_PROFILING
335 help
336 This tracer profiles all likely and unlikely macros
337 in the kernel. It will display the results in:
338
339 /sys/kernel/debug/tracing/trace_stat/branch_annotated
340
341 Note: this will add a significant overhead; only turn this
342 on if you need to profile the system's use of these macros.
343
344config PROFILE_ALL_BRANCHES
345 bool "Profile all if conditionals"
346 select TRACE_BRANCH_PROFILING
347 help
348 This tracer profiles all branch conditions. Every if ()
349 taken in the kernel is recorded whether it hit or miss.
350 The results will be displayed in:
351
352 /sys/kernel/debug/tracing/trace_stat/branch_all
353
354 This option also enables the likely/unlikely profiler.
355
356 This configuration, when enabled, will impose a great overhead
357 on the system. This should only be enabled when the system
358 is to be analyzed in much detail.
359endchoice
360
361config TRACING_BRANCHES
362 bool
363 help
364 Selected by tracers that will trace the likely and unlikely
365 conditions. This prevents the tracers themselves from being
366 profiled. Profiling the tracing infrastructure can only happen
367 when the likelys and unlikelys are not being traced.
368
369config BRANCH_TRACER
370 bool "Trace likely/unlikely instances"
371 depends on TRACE_BRANCH_PROFILING
372 select TRACING_BRANCHES
373 help
374 This traces the events of likely and unlikely condition
375 calls in the kernel. The difference between this and the
376 "Trace likely/unlikely profiler" is that this is not a
377 histogram of the callers, but actually places the calling
378 events into a running trace buffer to see when and where the
379 events happened, as well as their results.
380
381 Say N if unsure.
382
383config STACK_TRACER
384 bool "Trace max stack"
385 depends on HAVE_FUNCTION_TRACER
386 select FUNCTION_TRACER
387 select STACKTRACE
388 select KALLSYMS
389 help
390 This special tracer records the maximum stack footprint of the
391 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
392
393 This tracer works by hooking into every function call that the
394 kernel executes, and keeping a maximum stack depth value and
395 stack-trace saved. If this is configured with DYNAMIC_FTRACE
396 then it will not have any overhead while the stack tracer
397 is disabled.
398
399 To enable the stack tracer on bootup, pass in 'stacktrace'
400 on the kernel command line.
401
402 The stack tracer can also be enabled or disabled via the
403 sysctl kernel.stack_tracer_enabled
404
405 Say N if unsure.
406
407config BLK_DEV_IO_TRACE
408 bool "Support for tracing block IO actions"
409 depends on SYSFS
410 depends on BLOCK
411 select RELAY
412 select DEBUG_FS
413 select TRACEPOINTS
414 select GENERIC_TRACER
415 select STACKTRACE
416 help
417 Say Y here if you want to be able to trace the block layer actions
418 on a given queue. Tracing allows you to see any traffic happening
419 on a block device queue. For more information (and the userspace
420 support tools needed), fetch the blktrace tools from:
421
422 git://git.kernel.dk/blktrace.git
423
424 Tracing also is possible using the ftrace interface, e.g.:
425
426 echo 1 > /sys/block/sda/sda1/trace/enable
427 echo blk > /sys/kernel/debug/tracing/current_tracer
428 cat /sys/kernel/debug/tracing/trace_pipe
429
430 If unsure, say N.
431
432config KPROBE_EVENT
433 depends on KPROBES
434 depends on HAVE_REGS_AND_STACK_ACCESS_API
435 bool "Enable kprobes-based dynamic events"
436 select TRACING
437 select PROBE_EVENTS
438 default y
439 help
440 This allows the user to add tracing events (similar to tracepoints)
441 on the fly via the ftrace interface. See
442 Documentation/trace/kprobetrace.txt for more details.
443
444 Those events can be inserted wherever kprobes can probe, and record
445 various register and memory values.
446
447 This option is also required by perf-probe subcommand of perf tools.
448 If you want to use perf tools, this option is strongly recommended.
449
450config UPROBE_EVENT
451 bool "Enable uprobes-based dynamic events"
452 depends on ARCH_SUPPORTS_UPROBES
453 depends on MMU
454 depends on PERF_EVENTS
455 select UPROBES
456 select PROBE_EVENTS
457 select TRACING
458 default n
459 help
460 This allows the user to add tracing events on top of userspace
461 dynamic events (similar to tracepoints) on the fly via the trace
462 events interface. Those events can be inserted wherever uprobes
463 can probe, and record various registers.
464 This option is required if you plan to use perf-probe subcommand
465 of perf tools on user space applications.
466
467config BPF_EVENTS
468 depends on BPF_SYSCALL
469 depends on (KPROBE_EVENT || UPROBE_EVENT) && PERF_EVENTS
470 bool
471 default y
472 help
473 This allows the user to attach BPF programs to kprobe events.
474
475config PROBE_EVENTS
476 def_bool n
477
478config DYNAMIC_FTRACE
479 bool "enable/disable function tracing dynamically"
480 depends on FUNCTION_TRACER
481 depends on HAVE_DYNAMIC_FTRACE
482 default y
483 help
484 This option will modify all the calls to function tracing
485 dynamically (will patch them out of the binary image and
486 replace them with a No-Op instruction) on boot up. During
487 compile time, a table is made of all the locations that ftrace
488 can function trace, and this table is linked into the kernel
489 image. When this is enabled, functions can be individually
490 enabled, and the functions not enabled will not affect
491 performance of the system.
492
493 See the files in /sys/kernel/debug/tracing:
494 available_filter_functions
495 set_ftrace_filter
496 set_ftrace_notrace
497
498 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
499 otherwise has native performance as long as no tracing is active.
500
501config DYNAMIC_FTRACE_WITH_REGS
502 def_bool y
503 depends on DYNAMIC_FTRACE
504 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
505
506config FUNCTION_PROFILER
507 bool "Kernel function profiler"
508 depends on FUNCTION_TRACER
509 default n
510 help
511 This option enables the kernel function profiler. A file is created
512 in debugfs called function_profile_enabled which defaults to zero.
513 When a 1 is echoed into this file profiling begins, and when a
514 zero is entered, profiling stops. A "functions" file is created in
515 the trace_stats directory; this file shows the list of functions that
516 have been hit and their counters.
517
518 If in doubt, say N.
519
520config FTRACE_MCOUNT_RECORD
521 def_bool y
522 depends on DYNAMIC_FTRACE
523 depends on HAVE_FTRACE_MCOUNT_RECORD
524
525config FTRACE_SELFTEST
526 bool
527
528config FTRACE_STARTUP_TEST
529 bool "Perform a startup test on ftrace"
530 depends on GENERIC_TRACER
531 select FTRACE_SELFTEST
532 help
533 This option performs a series of startup tests on ftrace. On bootup
534 a series of tests are made to verify that the tracer is
535 functioning properly. It will do tests on all the configured
536 tracers of ftrace.
537
538config EVENT_TRACE_TEST_SYSCALLS
539 bool "Run selftest on syscall events"
540 depends on FTRACE_STARTUP_TEST
541 help
542 This option will also enable testing every syscall event.
543 It only enables the event and disables it and runs various loads
544 with the event enabled. This adds a bit more time for kernel boot
545 up since it runs this on every system call defined.
546
547 TBD - enable a way to actually call the syscalls as we test their
548 events
549
550config MMIOTRACE
551 bool "Memory mapped IO tracing"
552 depends on HAVE_MMIOTRACE_SUPPORT && PCI
553 select GENERIC_TRACER
554 help
555 Mmiotrace traces Memory Mapped I/O access and is meant for
556 debugging and reverse engineering. It is called from the ioremap
557 implementation and works via page faults. Tracing is disabled by
558 default and can be enabled at run-time.
559
560 See Documentation/trace/mmiotrace.txt.
561 If you are not helping to develop drivers, say N.
562
563config TRACING_MAP
564 bool
565 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
566 help
567 tracing_map is a special-purpose lock-free map for tracing,
568 separated out as a stand-alone facility in order to allow it
569 to be shared between multiple tracers. It isn't meant to be
570 generally used outside of that context, and is normally
571 selected by tracers that use it.
572
573config HIST_TRIGGERS
574 bool "Histogram triggers"
575 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
576 select TRACING_MAP
577 select TRACING
578 default n
579 help
580 Hist triggers allow one or more arbitrary trace event fields
581 to be aggregated into hash tables and dumped to stdout by
582 reading a debugfs/tracefs file. They're useful for
583 gathering quick and dirty (though precise) summaries of
584 event activity as an initial guide for further investigation
585 using more advanced tools.
586
587 See Documentation/trace/events.txt.
588 If in doubt, say N.
589
590config MMIOTRACE_TEST
591 tristate "Test module for mmiotrace"
592 depends on MMIOTRACE && m
593 help
594 This is a dumb module for testing mmiotrace. It is very dangerous
595 as it will write garbage to IO memory starting at a given address.
596 However, it should be safe to use on e.g. unused portion of VRAM.
597
598 Say N, unless you absolutely know what you are doing.
599
600config TRACEPOINT_BENCHMARK
601 bool "Add tracepoint that benchmarks tracepoints"
602 help
603 This option creates the tracepoint "benchmark:benchmark_event".
604 When the tracepoint is enabled, it kicks off a kernel thread that
605 goes into an infinite loop (calling cond_sched() to let other tasks
606 run), and calls the tracepoint. Each iteration will record the time
607 it took to write to the tracepoint and the next iteration that
608 data will be passed to the tracepoint itself. That is, the tracepoint
609 will report the time it took to do the previous tracepoint.
610 The string written to the tracepoint is a static string of 128 bytes
611 to keep the time the same. The initial string is simply a write of
612 "START". The second string records the cold cache time of the first
613 write which is not added to the rest of the calculations.
614
615 As it is a tight loop, it benchmarks as hot cache. That's fine because
616 we care most about hot paths that are probably in cache already.
617
618 An example of the output:
619
620 START
621 first=3672 [COLD CACHED]
622 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
623 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
624 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
625 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
626 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
627 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
628
629
630config RING_BUFFER_BENCHMARK
631 tristate "Ring buffer benchmark stress tester"
632 depends on RING_BUFFER
633 help
634 This option creates a test to stress the ring buffer and benchmark it.
635 It creates its own ring buffer such that it will not interfere with
636 any other users of the ring buffer (such as ftrace). It then creates
637 a producer and consumer that will run for 10 seconds and sleep for
638 10 seconds. Each interval it will print out the number of events
639 it recorded and give a rough estimate of how long each iteration took.
640
641 It does not disable interrupts or raise its priority, so it may be
642 affected by processes that are running.
643
644 If unsure, say N.
645
646config RING_BUFFER_STARTUP_TEST
647 bool "Ring buffer startup self test"
648 depends on RING_BUFFER
649 help
650 Run a simple self test on the ring buffer on boot up. Late in the
651 kernel boot sequence, the test will start that kicks off
652 a thread per cpu. Each thread will write various size events
653 into the ring buffer. Another thread is created to send IPIs
654 to each of the threads, where the IPI handler will also write
655 to the ring buffer, to test/stress the nesting ability.
656 If any anomalies are discovered, a warning will be displayed
657 and all ring buffers will be disabled.
658
659 The test runs for 10 seconds. This will slow your boot time
660 by at least 10 more seconds.
661
662 At the end of the test, statics and more checks are done.
663 It will output the stats of each per cpu buffer. What
664 was written, the sizes, what was read, what was lost, and
665 other similar details.
666
667 If unsure, say N
668
669config TRACE_ENUM_MAP_FILE
670 bool "Show enum mappings for trace events"
671 depends on TRACING
672 help
673 The "print fmt" of the trace events will show the enum names instead
674 of their values. This can cause problems for user space tools that
675 use this string to parse the raw data as user space does not know
676 how to convert the string to its value.
677
678 To fix this, there's a special macro in the kernel that can be used
679 to convert the enum into its value. If this macro is used, then the
680 print fmt strings will have the enums converted to their values.
681
682 If something does not get converted properly, this option can be
683 used to show what enums the kernel tried to convert.
684
685 This option is for debugging the enum conversions. A file is created
686 in the tracing directory called "enum_map" that will show the enum
687 names matched with their values and what trace event system they
688 belong too.
689
690 Normally, the mapping of the strings to values will be freed after
691 boot up or module load. With this option, they will not be freed, as
692 they are needed for the "enum_map" file. Enabling this option will
693 increase the memory footprint of the running kernel.
694
695 If unsure, say N
696
697config TRACING_EVENTS_GPIO
698 bool "Trace gpio events"
699 depends on GPIOLIB
700 default y
701 help
702 Enable tracing events for gpio subsystem
703
704endif # FTRACE
705
706endif # TRACING_SUPPORT
707
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Architectures that offer an FUNCTION_TRACER implementation should
4# select HAVE_FUNCTION_TRACER:
5#
6
7config USER_STACKTRACE_SUPPORT
8 bool
9
10config NOP_TRACER
11 bool
12
13config HAVE_FUNCTION_TRACER
14 bool
15 help
16 See Documentation/trace/ftrace-design.rst
17
18config HAVE_FUNCTION_GRAPH_TRACER
19 bool
20 help
21 See Documentation/trace/ftrace-design.rst
22
23config HAVE_DYNAMIC_FTRACE
24 bool
25 help
26 See Documentation/trace/ftrace-design.rst
27
28config HAVE_DYNAMIC_FTRACE_WITH_REGS
29 bool
30
31config HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
32 bool
33
34config HAVE_FTRACE_MCOUNT_RECORD
35 bool
36 help
37 See Documentation/trace/ftrace-design.rst
38
39config HAVE_SYSCALL_TRACEPOINTS
40 bool
41 help
42 See Documentation/trace/ftrace-design.rst
43
44config HAVE_FENTRY
45 bool
46 help
47 Arch supports the gcc options -pg with -mfentry
48
49config HAVE_NOP_MCOUNT
50 bool
51 help
52 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
53
54config HAVE_C_RECORDMCOUNT
55 bool
56 help
57 C version of recordmcount available?
58
59config TRACER_MAX_TRACE
60 bool
61
62config TRACE_CLOCK
63 bool
64
65config RING_BUFFER
66 bool
67 select TRACE_CLOCK
68 select IRQ_WORK
69
70config EVENT_TRACING
71 select CONTEXT_SWITCH_TRACER
72 select GLOB
73 bool
74
75config CONTEXT_SWITCH_TRACER
76 bool
77
78config RING_BUFFER_ALLOW_SWAP
79 bool
80 help
81 Allow the use of ring_buffer_swap_cpu.
82 Adds a very slight overhead to tracing when enabled.
83
84config PREEMPTIRQ_TRACEPOINTS
85 bool
86 depends on TRACE_PREEMPT_TOGGLE || TRACE_IRQFLAGS
87 select TRACING
88 default y
89 help
90 Create preempt/irq toggle tracepoints if needed, so that other parts
91 of the kernel can use them to generate or add hooks to them.
92
93# All tracer options should select GENERIC_TRACER. For those options that are
94# enabled by all tracers (context switch and event tracer) they select TRACING.
95# This allows those options to appear when no other tracer is selected. But the
96# options do not appear when something else selects it. We need the two options
97# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
98# hiding of the automatic options.
99
100config TRACING
101 bool
102 select RING_BUFFER
103 select STACKTRACE if STACKTRACE_SUPPORT
104 select TRACEPOINTS
105 select NOP_TRACER
106 select BINARY_PRINTF
107 select EVENT_TRACING
108 select TRACE_CLOCK
109
110config GENERIC_TRACER
111 bool
112 select TRACING
113
114#
115# Minimum requirements an architecture has to meet for us to
116# be able to offer generic tracing facilities:
117#
118config TRACING_SUPPORT
119 bool
120 depends on TRACE_IRQFLAGS_SUPPORT
121 depends on STACKTRACE_SUPPORT
122 default y
123
124if TRACING_SUPPORT
125
126menuconfig FTRACE
127 bool "Tracers"
128 default y if DEBUG_KERNEL
129 help
130 Enable the kernel tracing infrastructure.
131
132if FTRACE
133
134config BOOTTIME_TRACING
135 bool "Boot-time Tracing support"
136 depends on TRACING
137 select BOOT_CONFIG
138 help
139 Enable developer to setup ftrace subsystem via supplemental
140 kernel cmdline at boot time for debugging (tracing) driver
141 initialization and boot process.
142
143config FUNCTION_TRACER
144 bool "Kernel Function Tracer"
145 depends on HAVE_FUNCTION_TRACER
146 select KALLSYMS
147 select GENERIC_TRACER
148 select CONTEXT_SWITCH_TRACER
149 select GLOB
150 select TASKS_RCU if PREEMPTION
151 select TASKS_RUDE_RCU
152 help
153 Enable the kernel to trace every kernel function. This is done
154 by using a compiler feature to insert a small, 5-byte No-Operation
155 instruction at the beginning of every kernel function, which NOP
156 sequence is then dynamically patched into a tracer call when
157 tracing is enabled by the administrator. If it's runtime disabled
158 (the bootup default), then the overhead of the instructions is very
159 small and not measurable even in micro-benchmarks.
160
161config FUNCTION_GRAPH_TRACER
162 bool "Kernel Function Graph Tracer"
163 depends on HAVE_FUNCTION_GRAPH_TRACER
164 depends on FUNCTION_TRACER
165 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
166 default y
167 help
168 Enable the kernel to trace a function at both its return
169 and its entry.
170 Its first purpose is to trace the duration of functions and
171 draw a call graph for each thread with some information like
172 the return value. This is done by setting the current return
173 address on the current task structure into a stack of calls.
174
175config DYNAMIC_FTRACE
176 bool "enable/disable function tracing dynamically"
177 depends on FUNCTION_TRACER
178 depends on HAVE_DYNAMIC_FTRACE
179 default y
180 help
181 This option will modify all the calls to function tracing
182 dynamically (will patch them out of the binary image and
183 replace them with a No-Op instruction) on boot up. During
184 compile time, a table is made of all the locations that ftrace
185 can function trace, and this table is linked into the kernel
186 image. When this is enabled, functions can be individually
187 enabled, and the functions not enabled will not affect
188 performance of the system.
189
190 See the files in /sys/kernel/debug/tracing:
191 available_filter_functions
192 set_ftrace_filter
193 set_ftrace_notrace
194
195 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
196 otherwise has native performance as long as no tracing is active.
197
198config DYNAMIC_FTRACE_WITH_REGS
199 def_bool y
200 depends on DYNAMIC_FTRACE
201 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
202
203config DYNAMIC_FTRACE_WITH_DIRECT_CALLS
204 def_bool y
205 depends on DYNAMIC_FTRACE
206 depends on HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
207
208config FUNCTION_PROFILER
209 bool "Kernel function profiler"
210 depends on FUNCTION_TRACER
211 default n
212 help
213 This option enables the kernel function profiler. A file is created
214 in debugfs called function_profile_enabled which defaults to zero.
215 When a 1 is echoed into this file profiling begins, and when a
216 zero is entered, profiling stops. A "functions" file is created in
217 the trace_stat directory; this file shows the list of functions that
218 have been hit and their counters.
219
220 If in doubt, say N.
221
222config STACK_TRACER
223 bool "Trace max stack"
224 depends on HAVE_FUNCTION_TRACER
225 select FUNCTION_TRACER
226 select STACKTRACE
227 select KALLSYMS
228 help
229 This special tracer records the maximum stack footprint of the
230 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
231
232 This tracer works by hooking into every function call that the
233 kernel executes, and keeping a maximum stack depth value and
234 stack-trace saved. If this is configured with DYNAMIC_FTRACE
235 then it will not have any overhead while the stack tracer
236 is disabled.
237
238 To enable the stack tracer on bootup, pass in 'stacktrace'
239 on the kernel command line.
240
241 The stack tracer can also be enabled or disabled via the
242 sysctl kernel.stack_tracer_enabled
243
244 Say N if unsure.
245
246config TRACE_PREEMPT_TOGGLE
247 bool
248 help
249 Enables hooks which will be called when preemption is first disabled,
250 and last enabled.
251
252config IRQSOFF_TRACER
253 bool "Interrupts-off Latency Tracer"
254 default n
255 depends on TRACE_IRQFLAGS_SUPPORT
256 depends on !ARCH_USES_GETTIMEOFFSET
257 select TRACE_IRQFLAGS
258 select GENERIC_TRACER
259 select TRACER_MAX_TRACE
260 select RING_BUFFER_ALLOW_SWAP
261 select TRACER_SNAPSHOT
262 select TRACER_SNAPSHOT_PER_CPU_SWAP
263 help
264 This option measures the time spent in irqs-off critical
265 sections, with microsecond accuracy.
266
267 The default measurement method is a maximum search, which is
268 disabled by default and can be runtime (re-)started
269 via:
270
271 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
272
273 (Note that kernel size and overhead increase with this option
274 enabled. This option and the preempt-off timing option can be
275 used together or separately.)
276
277config PREEMPT_TRACER
278 bool "Preemption-off Latency Tracer"
279 default n
280 depends on !ARCH_USES_GETTIMEOFFSET
281 depends on PREEMPTION
282 select GENERIC_TRACER
283 select TRACER_MAX_TRACE
284 select RING_BUFFER_ALLOW_SWAP
285 select TRACER_SNAPSHOT
286 select TRACER_SNAPSHOT_PER_CPU_SWAP
287 select TRACE_PREEMPT_TOGGLE
288 help
289 This option measures the time spent in preemption-off critical
290 sections, with microsecond accuracy.
291
292 The default measurement method is a maximum search, which is
293 disabled by default and can be runtime (re-)started
294 via:
295
296 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
297
298 (Note that kernel size and overhead increase with this option
299 enabled. This option and the irqs-off timing option can be
300 used together or separately.)
301
302config SCHED_TRACER
303 bool "Scheduling Latency Tracer"
304 select GENERIC_TRACER
305 select CONTEXT_SWITCH_TRACER
306 select TRACER_MAX_TRACE
307 select TRACER_SNAPSHOT
308 help
309 This tracer tracks the latency of the highest priority task
310 to be scheduled in, starting from the point it has woken up.
311
312config HWLAT_TRACER
313 bool "Tracer to detect hardware latencies (like SMIs)"
314 select GENERIC_TRACER
315 help
316 This tracer, when enabled will create one or more kernel threads,
317 depending on what the cpumask file is set to, which each thread
318 spinning in a loop looking for interruptions caused by
319 something other than the kernel. For example, if a
320 System Management Interrupt (SMI) takes a noticeable amount of
321 time, this tracer will detect it. This is useful for testing
322 if a system is reliable for Real Time tasks.
323
324 Some files are created in the tracing directory when this
325 is enabled:
326
327 hwlat_detector/width - time in usecs for how long to spin for
328 hwlat_detector/window - time in usecs between the start of each
329 iteration
330
331 A kernel thread is created that will spin with interrupts disabled
332 for "width" microseconds in every "window" cycle. It will not spin
333 for "window - width" microseconds, where the system can
334 continue to operate.
335
336 The output will appear in the trace and trace_pipe files.
337
338 When the tracer is not running, it has no affect on the system,
339 but when it is running, it can cause the system to be
340 periodically non responsive. Do not run this tracer on a
341 production system.
342
343 To enable this tracer, echo in "hwlat" into the current_tracer
344 file. Every time a latency is greater than tracing_thresh, it will
345 be recorded into the ring buffer.
346
347config MMIOTRACE
348 bool "Memory mapped IO tracing"
349 depends on HAVE_MMIOTRACE_SUPPORT && PCI
350 select GENERIC_TRACER
351 help
352 Mmiotrace traces Memory Mapped I/O access and is meant for
353 debugging and reverse engineering. It is called from the ioremap
354 implementation and works via page faults. Tracing is disabled by
355 default and can be enabled at run-time.
356
357 See Documentation/trace/mmiotrace.rst.
358 If you are not helping to develop drivers, say N.
359
360config ENABLE_DEFAULT_TRACERS
361 bool "Trace process context switches and events"
362 depends on !GENERIC_TRACER
363 select TRACING
364 help
365 This tracer hooks to various trace points in the kernel,
366 allowing the user to pick and choose which trace point they
367 want to trace. It also includes the sched_switch tracer plugin.
368
369config FTRACE_SYSCALLS
370 bool "Trace syscalls"
371 depends on HAVE_SYSCALL_TRACEPOINTS
372 select GENERIC_TRACER
373 select KALLSYMS
374 help
375 Basic tracer to catch the syscall entry and exit events.
376
377config TRACER_SNAPSHOT
378 bool "Create a snapshot trace buffer"
379 select TRACER_MAX_TRACE
380 help
381 Allow tracing users to take snapshot of the current buffer using the
382 ftrace interface, e.g.:
383
384 echo 1 > /sys/kernel/debug/tracing/snapshot
385 cat snapshot
386
387config TRACER_SNAPSHOT_PER_CPU_SWAP
388 bool "Allow snapshot to swap per CPU"
389 depends on TRACER_SNAPSHOT
390 select RING_BUFFER_ALLOW_SWAP
391 help
392 Allow doing a snapshot of a single CPU buffer instead of a
393 full swap (all buffers). If this is set, then the following is
394 allowed:
395
396 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
397
398 After which, only the tracing buffer for CPU 2 was swapped with
399 the main tracing buffer, and the other CPU buffers remain the same.
400
401 When this is enabled, this adds a little more overhead to the
402 trace recording, as it needs to add some checks to synchronize
403 recording with swaps. But this does not affect the performance
404 of the overall system. This is enabled by default when the preempt
405 or irq latency tracers are enabled, as those need to swap as well
406 and already adds the overhead (plus a lot more).
407
408config TRACE_BRANCH_PROFILING
409 bool
410 select GENERIC_TRACER
411
412choice
413 prompt "Branch Profiling"
414 default BRANCH_PROFILE_NONE
415 help
416 The branch profiling is a software profiler. It will add hooks
417 into the C conditionals to test which path a branch takes.
418
419 The likely/unlikely profiler only looks at the conditions that
420 are annotated with a likely or unlikely macro.
421
422 The "all branch" profiler will profile every if-statement in the
423 kernel. This profiler will also enable the likely/unlikely
424 profiler.
425
426 Either of the above profilers adds a bit of overhead to the system.
427 If unsure, choose "No branch profiling".
428
429config BRANCH_PROFILE_NONE
430 bool "No branch profiling"
431 help
432 No branch profiling. Branch profiling adds a bit of overhead.
433 Only enable it if you want to analyse the branching behavior.
434 Otherwise keep it disabled.
435
436config PROFILE_ANNOTATED_BRANCHES
437 bool "Trace likely/unlikely profiler"
438 select TRACE_BRANCH_PROFILING
439 help
440 This tracer profiles all likely and unlikely macros
441 in the kernel. It will display the results in:
442
443 /sys/kernel/debug/tracing/trace_stat/branch_annotated
444
445 Note: this will add a significant overhead; only turn this
446 on if you need to profile the system's use of these macros.
447
448config PROFILE_ALL_BRANCHES
449 bool "Profile all if conditionals" if !FORTIFY_SOURCE
450 select TRACE_BRANCH_PROFILING
451 help
452 This tracer profiles all branch conditions. Every if ()
453 taken in the kernel is recorded whether it hit or miss.
454 The results will be displayed in:
455
456 /sys/kernel/debug/tracing/trace_stat/branch_all
457
458 This option also enables the likely/unlikely profiler.
459
460 This configuration, when enabled, will impose a great overhead
461 on the system. This should only be enabled when the system
462 is to be analyzed in much detail.
463endchoice
464
465config TRACING_BRANCHES
466 bool
467 help
468 Selected by tracers that will trace the likely and unlikely
469 conditions. This prevents the tracers themselves from being
470 profiled. Profiling the tracing infrastructure can only happen
471 when the likelys and unlikelys are not being traced.
472
473config BRANCH_TRACER
474 bool "Trace likely/unlikely instances"
475 depends on TRACE_BRANCH_PROFILING
476 select TRACING_BRANCHES
477 help
478 This traces the events of likely and unlikely condition
479 calls in the kernel. The difference between this and the
480 "Trace likely/unlikely profiler" is that this is not a
481 histogram of the callers, but actually places the calling
482 events into a running trace buffer to see when and where the
483 events happened, as well as their results.
484
485 Say N if unsure.
486
487config BLK_DEV_IO_TRACE
488 bool "Support for tracing block IO actions"
489 depends on SYSFS
490 depends on BLOCK
491 select RELAY
492 select DEBUG_FS
493 select TRACEPOINTS
494 select GENERIC_TRACER
495 select STACKTRACE
496 help
497 Say Y here if you want to be able to trace the block layer actions
498 on a given queue. Tracing allows you to see any traffic happening
499 on a block device queue. For more information (and the userspace
500 support tools needed), fetch the blktrace tools from:
501
502 git://git.kernel.dk/blktrace.git
503
504 Tracing also is possible using the ftrace interface, e.g.:
505
506 echo 1 > /sys/block/sda/sda1/trace/enable
507 echo blk > /sys/kernel/debug/tracing/current_tracer
508 cat /sys/kernel/debug/tracing/trace_pipe
509
510 If unsure, say N.
511
512config KPROBE_EVENTS
513 depends on KPROBES
514 depends on HAVE_REGS_AND_STACK_ACCESS_API
515 bool "Enable kprobes-based dynamic events"
516 select TRACING
517 select PROBE_EVENTS
518 select DYNAMIC_EVENTS
519 default y
520 help
521 This allows the user to add tracing events (similar to tracepoints)
522 on the fly via the ftrace interface. See
523 Documentation/trace/kprobetrace.rst for more details.
524
525 Those events can be inserted wherever kprobes can probe, and record
526 various register and memory values.
527
528 This option is also required by perf-probe subcommand of perf tools.
529 If you want to use perf tools, this option is strongly recommended.
530
531config KPROBE_EVENTS_ON_NOTRACE
532 bool "Do NOT protect notrace function from kprobe events"
533 depends on KPROBE_EVENTS
534 depends on KPROBES_ON_FTRACE
535 default n
536 help
537 This is only for the developers who want to debug ftrace itself
538 using kprobe events.
539
540 If kprobes can use ftrace instead of breakpoint, ftrace related
541 functions are protected from kprobe-events to prevent an infinit
542 recursion or any unexpected execution path which leads to a kernel
543 crash.
544
545 This option disables such protection and allows you to put kprobe
546 events on ftrace functions for debugging ftrace by itself.
547 Note that this might let you shoot yourself in the foot.
548
549 If unsure, say N.
550
551config UPROBE_EVENTS
552 bool "Enable uprobes-based dynamic events"
553 depends on ARCH_SUPPORTS_UPROBES
554 depends on MMU
555 depends on PERF_EVENTS
556 select UPROBES
557 select PROBE_EVENTS
558 select DYNAMIC_EVENTS
559 select TRACING
560 default y
561 help
562 This allows the user to add tracing events on top of userspace
563 dynamic events (similar to tracepoints) on the fly via the trace
564 events interface. Those events can be inserted wherever uprobes
565 can probe, and record various registers.
566 This option is required if you plan to use perf-probe subcommand
567 of perf tools on user space applications.
568
569config BPF_EVENTS
570 depends on BPF_SYSCALL
571 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
572 bool
573 default y
574 help
575 This allows the user to attach BPF programs to kprobe, uprobe, and
576 tracepoint events.
577
578config DYNAMIC_EVENTS
579 def_bool n
580
581config PROBE_EVENTS
582 def_bool n
583
584config BPF_KPROBE_OVERRIDE
585 bool "Enable BPF programs to override a kprobed function"
586 depends on BPF_EVENTS
587 depends on FUNCTION_ERROR_INJECTION
588 default n
589 help
590 Allows BPF to override the execution of a probed function and
591 set a different return value. This is used for error injection.
592
593config FTRACE_MCOUNT_RECORD
594 def_bool y
595 depends on DYNAMIC_FTRACE
596 depends on HAVE_FTRACE_MCOUNT_RECORD
597
598config TRACING_MAP
599 bool
600 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
601 help
602 tracing_map is a special-purpose lock-free map for tracing,
603 separated out as a stand-alone facility in order to allow it
604 to be shared between multiple tracers. It isn't meant to be
605 generally used outside of that context, and is normally
606 selected by tracers that use it.
607
608config SYNTH_EVENTS
609 bool "Synthetic trace events"
610 select TRACING
611 select DYNAMIC_EVENTS
612 default n
613 help
614 Synthetic events are user-defined trace events that can be
615 used to combine data from other trace events or in fact any
616 data source. Synthetic events can be generated indirectly
617 via the trace() action of histogram triggers or directly
618 by way of an in-kernel API.
619
620 See Documentation/trace/events.rst or
621 Documentation/trace/histogram.rst for details and examples.
622
623 If in doubt, say N.
624
625config HIST_TRIGGERS
626 bool "Histogram triggers"
627 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
628 select TRACING_MAP
629 select TRACING
630 select DYNAMIC_EVENTS
631 select SYNTH_EVENTS
632 default n
633 help
634 Hist triggers allow one or more arbitrary trace event fields
635 to be aggregated into hash tables and dumped to stdout by
636 reading a debugfs/tracefs file. They're useful for
637 gathering quick and dirty (though precise) summaries of
638 event activity as an initial guide for further investigation
639 using more advanced tools.
640
641 Inter-event tracing of quantities such as latencies is also
642 supported using hist triggers under this option.
643
644 See Documentation/trace/histogram.rst.
645 If in doubt, say N.
646
647config TRACE_EVENT_INJECT
648 bool "Trace event injection"
649 depends on TRACING
650 help
651 Allow user-space to inject a specific trace event into the ring
652 buffer. This is mainly used for testing purpose.
653
654 If unsure, say N.
655
656config TRACEPOINT_BENCHMARK
657 bool "Add tracepoint that benchmarks tracepoints"
658 help
659 This option creates the tracepoint "benchmark:benchmark_event".
660 When the tracepoint is enabled, it kicks off a kernel thread that
661 goes into an infinite loop (calling cond_sched() to let other tasks
662 run), and calls the tracepoint. Each iteration will record the time
663 it took to write to the tracepoint and the next iteration that
664 data will be passed to the tracepoint itself. That is, the tracepoint
665 will report the time it took to do the previous tracepoint.
666 The string written to the tracepoint is a static string of 128 bytes
667 to keep the time the same. The initial string is simply a write of
668 "START". The second string records the cold cache time of the first
669 write which is not added to the rest of the calculations.
670
671 As it is a tight loop, it benchmarks as hot cache. That's fine because
672 we care most about hot paths that are probably in cache already.
673
674 An example of the output:
675
676 START
677 first=3672 [COLD CACHED]
678 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
679 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
680 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
681 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
682 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
683 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
684
685
686config RING_BUFFER_BENCHMARK
687 tristate "Ring buffer benchmark stress tester"
688 depends on RING_BUFFER
689 help
690 This option creates a test to stress the ring buffer and benchmark it.
691 It creates its own ring buffer such that it will not interfere with
692 any other users of the ring buffer (such as ftrace). It then creates
693 a producer and consumer that will run for 10 seconds and sleep for
694 10 seconds. Each interval it will print out the number of events
695 it recorded and give a rough estimate of how long each iteration took.
696
697 It does not disable interrupts or raise its priority, so it may be
698 affected by processes that are running.
699
700 If unsure, say N.
701
702config TRACE_EVAL_MAP_FILE
703 bool "Show eval mappings for trace events"
704 depends on TRACING
705 help
706 The "print fmt" of the trace events will show the enum/sizeof names
707 instead of their values. This can cause problems for user space tools
708 that use this string to parse the raw data as user space does not know
709 how to convert the string to its value.
710
711 To fix this, there's a special macro in the kernel that can be used
712 to convert an enum/sizeof into its value. If this macro is used, then
713 the print fmt strings will be converted to their values.
714
715 If something does not get converted properly, this option can be
716 used to show what enums/sizeof the kernel tried to convert.
717
718 This option is for debugging the conversions. A file is created
719 in the tracing directory called "eval_map" that will show the
720 names matched with their values and what trace event system they
721 belong too.
722
723 Normally, the mapping of the strings to values will be freed after
724 boot up or module load. With this option, they will not be freed, as
725 they are needed for the "eval_map" file. Enabling this option will
726 increase the memory footprint of the running kernel.
727
728 If unsure, say N.
729
730config GCOV_PROFILE_FTRACE
731 bool "Enable GCOV profiling on ftrace subsystem"
732 depends on GCOV_KERNEL
733 help
734 Enable GCOV profiling on ftrace subsystem for checking
735 which functions/lines are tested.
736
737 If unsure, say N.
738
739 Note that on a kernel compiled with this config, ftrace will
740 run significantly slower.
741
742config FTRACE_SELFTEST
743 bool
744
745config FTRACE_STARTUP_TEST
746 bool "Perform a startup test on ftrace"
747 depends on GENERIC_TRACER
748 select FTRACE_SELFTEST
749 help
750 This option performs a series of startup tests on ftrace. On bootup
751 a series of tests are made to verify that the tracer is
752 functioning properly. It will do tests on all the configured
753 tracers of ftrace.
754
755config EVENT_TRACE_STARTUP_TEST
756 bool "Run selftest on trace events"
757 depends on FTRACE_STARTUP_TEST
758 default y
759 help
760 This option performs a test on all trace events in the system.
761 It basically just enables each event and runs some code that
762 will trigger events (not necessarily the event it enables)
763 This may take some time run as there are a lot of events.
764
765config EVENT_TRACE_TEST_SYSCALLS
766 bool "Run selftest on syscall events"
767 depends on EVENT_TRACE_STARTUP_TEST
768 help
769 This option will also enable testing every syscall event.
770 It only enables the event and disables it and runs various loads
771 with the event enabled. This adds a bit more time for kernel boot
772 up since it runs this on every system call defined.
773
774 TBD - enable a way to actually call the syscalls as we test their
775 events
776
777config RING_BUFFER_STARTUP_TEST
778 bool "Ring buffer startup self test"
779 depends on RING_BUFFER
780 help
781 Run a simple self test on the ring buffer on boot up. Late in the
782 kernel boot sequence, the test will start that kicks off
783 a thread per cpu. Each thread will write various size events
784 into the ring buffer. Another thread is created to send IPIs
785 to each of the threads, where the IPI handler will also write
786 to the ring buffer, to test/stress the nesting ability.
787 If any anomalies are discovered, a warning will be displayed
788 and all ring buffers will be disabled.
789
790 The test runs for 10 seconds. This will slow your boot time
791 by at least 10 more seconds.
792
793 At the end of the test, statics and more checks are done.
794 It will output the stats of each per cpu buffer. What
795 was written, the sizes, what was read, what was lost, and
796 other similar details.
797
798 If unsure, say N
799
800config MMIOTRACE_TEST
801 tristate "Test module for mmiotrace"
802 depends on MMIOTRACE && m
803 help
804 This is a dumb module for testing mmiotrace. It is very dangerous
805 as it will write garbage to IO memory starting at a given address.
806 However, it should be safe to use on e.g. unused portion of VRAM.
807
808 Say N, unless you absolutely know what you are doing.
809
810config PREEMPTIRQ_DELAY_TEST
811 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
812 depends on m
813 help
814 Select this option to build a test module that can help test latency
815 tracers by executing a preempt or irq disable section with a user
816 configurable delay. The module busy waits for the duration of the
817 critical section.
818
819 For example, the following invocation generates a burst of three
820 irq-disabled critical sections for 500us:
821 modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3
822
823 If unsure, say N
824
825config SYNTH_EVENT_GEN_TEST
826 tristate "Test module for in-kernel synthetic event generation"
827 depends on SYNTH_EVENTS
828 help
829 This option creates a test module to check the base
830 functionality of in-kernel synthetic event definition and
831 generation.
832
833 To test, insert the module, and then check the trace buffer
834 for the generated sample events.
835
836 If unsure, say N.
837
838config KPROBE_EVENT_GEN_TEST
839 tristate "Test module for in-kernel kprobe event generation"
840 depends on KPROBE_EVENTS
841 help
842 This option creates a test module to check the base
843 functionality of in-kernel kprobe event definition.
844
845 To test, insert the module, and then check the trace buffer
846 for the generated kprobe events.
847
848 If unsure, say N.
849
850config HIST_TRIGGERS_DEBUG
851 bool "Hist trigger debug support"
852 depends on HIST_TRIGGERS
853 help
854 Add "hist_debug" file for each event, which when read will
855 dump out a bunch of internal details about the hist triggers
856 defined on that event.
857
858 The hist_debug file serves a couple of purposes:
859
860 - Helps developers verify that nothing is broken.
861
862 - Provides educational information to support the details
863 of the hist trigger internals as described by
864 Documentation/trace/histogram-design.rst.
865
866 The hist_debug output only covers the data structures
867 related to the histogram definitions themselves and doesn't
868 display the internals of map buckets or variable values of
869 running histograms.
870
871 If unsure, say N.
872
873endif # FTRACE
874
875endif # TRACING_SUPPORT
876