xref: /openbmc/linux/kernel/trace/Kconfig (revision e15a5365)
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
877