1
2
3
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
86
87
88
89
90
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
109
110
111config TRACING_SUPPORT
112 bool
113
114
115
116
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 select TASKS_RCU if PREEMPT
139 help
140 Enable the kernel to trace every kernel function. This is done
141 by using a compiler feature to insert a small, 5-byte No-Operation
142 instruction at the beginning of every kernel function, which NOP
143 sequence is then dynamically patched into a tracer call when
144 tracing is enabled by the administrator. If it's runtime disabled
145 (the bootup default), then the overhead of the instructions is very
146 small and not measurable even in micro-benchmarks.
147
148config FUNCTION_GRAPH_TRACER
149 bool "Kernel Function Graph Tracer"
150 depends on HAVE_FUNCTION_GRAPH_TRACER
151 depends on FUNCTION_TRACER
152 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
153 default y
154 help
155 Enable the kernel to trace a function at both its return
156 and its entry.
157 Its first purpose is to trace the duration of functions and
158 draw a call graph for each thread with some information like
159 the return value. This is done by setting the current return
160 address on the current task structure into a stack of calls.
161
162
163config IRQSOFF_TRACER
164 bool "Interrupts-off Latency Tracer"
165 default n
166 depends on TRACE_IRQFLAGS_SUPPORT
167 depends on !ARCH_USES_GETTIMEOFFSET
168 select TRACE_IRQFLAGS
169 select GENERIC_TRACER
170 select TRACER_MAX_TRACE
171 select RING_BUFFER_ALLOW_SWAP
172 select TRACER_SNAPSHOT
173 select TRACER_SNAPSHOT_PER_CPU_SWAP
174 help
175 This option measures the time spent in irqs-off critical
176 sections, with microsecond accuracy.
177
178 The default measurement method is a maximum search, which is
179 disabled by default and can be runtime (re-)started
180 via:
181
182 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
183
184 (Note that kernel size and overhead increase with this option
185 enabled. This option and the preempt-off timing option can be
186 used together or separately.)
187
188config PREEMPT_TRACER
189 bool "Preemption-off Latency Tracer"
190 default n
191 depends on !ARCH_USES_GETTIMEOFFSET
192 depends on PREEMPT
193 select GENERIC_TRACER
194 select TRACER_MAX_TRACE
195 select RING_BUFFER_ALLOW_SWAP
196 select TRACER_SNAPSHOT
197 select TRACER_SNAPSHOT_PER_CPU_SWAP
198 help
199 This option measures the time spent in preemption-off critical
200 sections, with microsecond accuracy.
201
202 The default measurement method is a maximum search, which is
203 disabled by default and can be runtime (re-)started
204 via:
205
206 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
207
208 (Note that kernel size and overhead increase with this option
209 enabled. This option and the irqs-off timing option can be
210 used together or separately.)
211
212config SCHED_TRACER
213 bool "Scheduling Latency Tracer"
214 select GENERIC_TRACER
215 select CONTEXT_SWITCH_TRACER
216 select TRACER_MAX_TRACE
217 select TRACER_SNAPSHOT
218 help
219 This tracer tracks the latency of the highest priority task
220 to be scheduled in, starting from the point it has woken up.
221
222config HWLAT_TRACER
223 bool "Tracer to detect hardware latencies (like SMIs)"
224 select GENERIC_TRACER
225 help
226 This tracer, when enabled will create one or more kernel threads,
227 depening on what the cpumask file is set to, which each thread
228 spinning in a loop looking for interruptions caused by
229 something other than the kernel. For example, if a
230 System Management Interrupt (SMI) takes a noticeable amount of
231 time, this tracer will detect it. This is useful for testing
232 if a system is reliable for Real Time tasks.
233
234 Some files are created in the tracing directory when this
235 is enabled:
236
237 hwlat_detector/width - time in usecs for how long to spin for
238 hwlat_detector/window - time in usecs between the start of each
239 iteration
240
241 A kernel thread is created that will spin with interrupts disabled
242 for "width" microseconds in every "widow" cycle. It will not spin
243 for "window - width" microseconds, where the system can
244 continue to operate.
245
246 The output will appear in the trace and trace_pipe files.
247
248 When the tracer is not running, it has no affect on the system,
249 but when it is running, it can cause the system to be
250 periodically non responsive. Do not run this tracer on a
251 production system.
252
253 To enable this tracer, echo in "hwlat" into the current_tracer
254 file. Every time a latency is greater than tracing_thresh, it will
255 be recorded into the ring buffer.
256
257config ENABLE_DEFAULT_TRACERS
258 bool "Trace process context switches and events"
259 depends on !GENERIC_TRACER
260 select TRACING
261 help
262 This tracer hooks to various trace points in the kernel,
263 allowing the user to pick and choose which trace point they
264 want to trace. It also includes the sched_switch tracer plugin.
265
266config FTRACE_SYSCALLS
267 bool "Trace syscalls"
268 depends on HAVE_SYSCALL_TRACEPOINTS
269 select GENERIC_TRACER
270 select KALLSYMS
271 help
272 Basic tracer to catch the syscall entry and exit events.
273
274config TRACER_SNAPSHOT
275 bool "Create a snapshot trace buffer"
276 select TRACER_MAX_TRACE
277 help
278 Allow tracing users to take snapshot of the current buffer using the
279 ftrace interface, e.g.:
280
281 echo 1 > /sys/kernel/debug/tracing/snapshot
282 cat snapshot
283
284config TRACER_SNAPSHOT_PER_CPU_SWAP
285 bool "Allow snapshot to swap per CPU"
286 depends on TRACER_SNAPSHOT
287 select RING_BUFFER_ALLOW_SWAP
288 help
289 Allow doing a snapshot of a single CPU buffer instead of a
290 full swap (all buffers). If this is set, then the following is
291 allowed:
292
293 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
294
295 After which, only the tracing buffer for CPU 2 was swapped with
296 the main tracing buffer, and the other CPU buffers remain the same.
297
298 When this is enabled, this adds a little more overhead to the
299 trace recording, as it needs to add some checks to synchronize
300 recording with swaps. But this does not affect the performance
301 of the overall system. This is enabled by default when the preempt
302 or irq latency tracers are enabled, as those need to swap as well
303 and already adds the overhead (plus a lot more).
304
305config TRACE_BRANCH_PROFILING
306 bool
307 select GENERIC_TRACER
308
309choice
310 prompt "Branch Profiling"
311 default BRANCH_PROFILE_NONE
312 help
313 The branch profiling is a software profiler. It will add hooks
314 into the C conditionals to test which path a branch takes.
315
316 The likely/unlikely profiler only looks at the conditions that
317 are annotated with a likely or unlikely macro.
318
319 The "all branch" profiler will profile every if-statement in the
320 kernel. This profiler will also enable the likely/unlikely
321 profiler.
322
323 Either of the above profilers adds a bit of overhead to the system.
324 If unsure, choose "No branch profiling".
325
326config BRANCH_PROFILE_NONE
327 bool "No branch profiling"
328 help
329 No branch profiling. Branch profiling adds a bit of overhead.
330 Only enable it if you want to analyse the branching behavior.
331 Otherwise keep it disabled.
332
333config PROFILE_ANNOTATED_BRANCHES
334 bool "Trace likely/unlikely profiler"
335 select TRACE_BRANCH_PROFILING
336 help
337 This tracer profiles all likely and unlikely macros
338 in the kernel. It will display the results in:
339
340 /sys/kernel/debug/tracing/trace_stat/branch_annotated
341
342 Note: this will add a significant overhead; only turn this
343 on if you need to profile the system's use of these macros.
344
345config PROFILE_ALL_BRANCHES
346 bool "Profile all if conditionals"
347 select TRACE_BRANCH_PROFILING
348 help
349 This tracer profiles all branch conditions. Every if ()
350 taken in the kernel is recorded whether it hit or miss.
351 The results will be displayed in:
352
353 /sys/kernel/debug/tracing/trace_stat/branch_all
354
355 This option also enables the likely/unlikely profiler.
356
357 This configuration, when enabled, will impose a great overhead
358 on the system. This should only be enabled when the system
359 is to be analyzed in much detail.
360endchoice
361
362config TRACING_BRANCHES
363 bool
364 help
365 Selected by tracers that will trace the likely and unlikely
366 conditions. This prevents the tracers themselves from being
367 profiled. Profiling the tracing infrastructure can only happen
368 when the likelys and unlikelys are not being traced.
369
370config BRANCH_TRACER
371 bool "Trace likely/unlikely instances"
372 depends on TRACE_BRANCH_PROFILING
373 select TRACING_BRANCHES
374 help
375 This traces the events of likely and unlikely condition
376 calls in the kernel. The difference between this and the
377 "Trace likely/unlikely profiler" is that this is not a
378 histogram of the callers, but actually places the calling
379 events into a running trace buffer to see when and where the
380 events happened, as well as their results.
381
382 Say N if unsure.
383
384config STACK_TRACER
385 bool "Trace max stack"
386 depends on HAVE_FUNCTION_TRACER
387 select FUNCTION_TRACER
388 select STACKTRACE
389 select KALLSYMS
390 help
391 This special tracer records the maximum stack footprint of the
392 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
393
394 This tracer works by hooking into every function call that the
395 kernel executes, and keeping a maximum stack depth value and
396 stack-trace saved. If this is configured with DYNAMIC_FTRACE
397 then it will not have any overhead while the stack tracer
398 is disabled.
399
400 To enable the stack tracer on bootup, pass in 'stacktrace'
401 on the kernel command line.
402
403 The stack tracer can also be enabled or disabled via the
404 sysctl kernel.stack_tracer_enabled
405
406 Say N if unsure.
407
408config BLK_DEV_IO_TRACE
409 bool "Support for tracing block IO actions"
410 depends on SYSFS
411 depends on BLOCK
412 select RELAY
413 select DEBUG_FS
414 select TRACEPOINTS
415 select GENERIC_TRACER
416 select STACKTRACE
417 help
418 Say Y here if you want to be able to trace the block layer actions
419 on a given queue. Tracing allows you to see any traffic happening
420 on a block device queue. For more information (and the userspace
421 support tools needed), fetch the blktrace tools from:
422
423 git://git.kernel.dk/blktrace.git
424
425 Tracing also is possible using the ftrace interface, e.g.:
426
427 echo 1 > /sys/block/sda/sda1/trace/enable
428 echo blk > /sys/kernel/debug/tracing/current_tracer
429 cat /sys/kernel/debug/tracing/trace_pipe
430
431 If unsure, say N.
432
433config KPROBE_EVENTS
434 depends on KPROBES
435 depends on HAVE_REGS_AND_STACK_ACCESS_API
436 bool "Enable kprobes-based dynamic events"
437 select TRACING
438 select PROBE_EVENTS
439 default y
440 help
441 This allows the user to add tracing events (similar to tracepoints)
442 on the fly via the ftrace interface. See
443 Documentation/trace/kprobetrace.txt for more details.
444
445 Those events can be inserted wherever kprobes can probe, and record
446 various register and memory values.
447
448 This option is also required by perf-probe subcommand of perf tools.
449 If you want to use perf tools, this option is strongly recommended.
450
451config UPROBE_EVENTS
452 bool "Enable uprobes-based dynamic events"
453 depends on ARCH_SUPPORTS_UPROBES
454 depends on MMU
455 depends on PERF_EVENTS
456 select UPROBES
457 select PROBE_EVENTS
458 select TRACING
459 default y
460 help
461 This allows the user to add tracing events on top of userspace
462 dynamic events (similar to tracepoints) on the fly via the trace
463 events interface. Those events can be inserted wherever uprobes
464 can probe, and record various registers.
465 This option is required if you plan to use perf-probe subcommand
466 of perf tools on user space applications.
467
468config BPF_EVENTS
469 depends on BPF_SYSCALL
470 depends on (KPROBE_EVENTS || UPROBE_EVENTS) && PERF_EVENTS
471 bool
472 default y
473 help
474 This allows the user to attach BPF programs to kprobe events.
475
476config PROBE_EVENTS
477 def_bool n
478
479config DYNAMIC_FTRACE
480 bool "enable/disable function tracing dynamically"
481 depends on FUNCTION_TRACER
482 depends on HAVE_DYNAMIC_FTRACE
483 default y
484 help
485 This option will modify all the calls to function tracing
486 dynamically (will patch them out of the binary image and
487 replace them with a No-Op instruction) on boot up. During
488 compile time, a table is made of all the locations that ftrace
489 can function trace, and this table is linked into the kernel
490 image. When this is enabled, functions can be individually
491 enabled, and the functions not enabled will not affect
492 performance of the system.
493
494 See the files in /sys/kernel/debug/tracing:
495 available_filter_functions
496 set_ftrace_filter
497 set_ftrace_notrace
498
499 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
500 otherwise has native performance as long as no tracing is active.
501
502config DYNAMIC_FTRACE_WITH_REGS
503 def_bool y
504 depends on DYNAMIC_FTRACE
505 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
506
507config FUNCTION_PROFILER
508 bool "Kernel function profiler"
509 depends on FUNCTION_TRACER
510 default n
511 help
512 This option enables the kernel function profiler. A file is created
513 in debugfs called function_profile_enabled which defaults to zero.
514 When a 1 is echoed into this file profiling begins, and when a
515 zero is entered, profiling stops. A "functions" file is created in
516 the trace_stats directory; this file shows the list of functions that
517 have been hit and their counters.
518
519 If in doubt, say N.
520
521config FTRACE_MCOUNT_RECORD
522 def_bool y
523 depends on DYNAMIC_FTRACE
524 depends on HAVE_FTRACE_MCOUNT_RECORD
525
526config FTRACE_SELFTEST
527 bool
528
529config FTRACE_STARTUP_TEST
530 bool "Perform a startup test on ftrace"
531 depends on GENERIC_TRACER
532 select FTRACE_SELFTEST
533 help
534 This option performs a series of startup tests on ftrace. On bootup
535 a series of tests are made to verify that the tracer is
536 functioning properly. It will do tests on all the configured
537 tracers of ftrace.
538
539config EVENT_TRACE_TEST_SYSCALLS
540 bool "Run selftest on syscall events"
541 depends on FTRACE_STARTUP_TEST
542 help
543 This option will also enable testing every syscall event.
544 It only enables the event and disables it and runs various loads
545 with the event enabled. This adds a bit more time for kernel boot
546 up since it runs this on every system call defined.
547
548 TBD - enable a way to actually call the syscalls as we test their
549 events
550
551config MMIOTRACE
552 bool "Memory mapped IO tracing"
553 depends on HAVE_MMIOTRACE_SUPPORT && PCI
554 select GENERIC_TRACER
555 help
556 Mmiotrace traces Memory Mapped I/O access and is meant for
557 debugging and reverse engineering. It is called from the ioremap
558 implementation and works via page faults. Tracing is disabled by
559 default and can be enabled at run-time.
560
561 See Documentation/trace/mmiotrace.txt.
562 If you are not helping to develop drivers, say N.
563
564config TRACING_MAP
565 bool
566 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
567 help
568 tracing_map is a special-purpose lock-free map for tracing,
569 separated out as a stand-alone facility in order to allow it
570 to be shared between multiple tracers. It isn't meant to be
571 generally used outside of that context, and is normally
572 selected by tracers that use it.
573
574config HIST_TRIGGERS
575 bool "Histogram triggers"
576 depends on ARCH_HAVE_NMI_SAFE_CMPXCHG
577 select TRACING_MAP
578 select TRACING
579 default n
580 help
581 Hist triggers allow one or more arbitrary trace event fields
582 to be aggregated into hash tables and dumped to stdout by
583 reading a debugfs/tracefs file. They're useful for
584 gathering quick and dirty (though precise) summaries of
585 event activity as an initial guide for further investigation
586 using more advanced tools.
587
588 See Documentation/trace/events.txt.
589 If in doubt, say N.
590
591config MMIOTRACE_TEST
592 tristate "Test module for mmiotrace"
593 depends on MMIOTRACE && m
594 help
595 This is a dumb module for testing mmiotrace. It is very dangerous
596 as it will write garbage to IO memory starting at a given address.
597 However, it should be safe to use on e.g. unused portion of VRAM.
598
599 Say N, unless you absolutely know what you are doing.
600
601config TRACEPOINT_BENCHMARK
602 bool "Add tracepoint that benchmarks tracepoints"
603 help
604 This option creates the tracepoint "benchmark:benchmark_event".
605 When the tracepoint is enabled, it kicks off a kernel thread that
606 goes into an infinite loop (calling cond_sched() to let other tasks
607 run), and calls the tracepoint. Each iteration will record the time
608 it took to write to the tracepoint and the next iteration that
609 data will be passed to the tracepoint itself. That is, the tracepoint
610 will report the time it took to do the previous tracepoint.
611 The string written to the tracepoint is a static string of 128 bytes
612 to keep the time the same. The initial string is simply a write of
613 "START". The second string records the cold cache time of the first
614 write which is not added to the rest of the calculations.
615
616 As it is a tight loop, it benchmarks as hot cache. That's fine because
617 we care most about hot paths that are probably in cache already.
618
619 An example of the output:
620
621 START
622 first=3672 [COLD CACHED]
623 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
624 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
625 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
626 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
627 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
628 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
629
630
631config RING_BUFFER_BENCHMARK
632 tristate "Ring buffer benchmark stress tester"
633 depends on RING_BUFFER
634 help
635 This option creates a test to stress the ring buffer and benchmark it.
636 It creates its own ring buffer such that it will not interfere with
637 any other users of the ring buffer (such as ftrace). It then creates
638 a producer and consumer that will run for 10 seconds and sleep for
639 10 seconds. Each interval it will print out the number of events
640 it recorded and give a rough estimate of how long each iteration took.
641
642 It does not disable interrupts or raise its priority, so it may be
643 affected by processes that are running.
644
645 If unsure, say N.
646
647config RING_BUFFER_STARTUP_TEST
648 bool "Ring buffer startup self test"
649 depends on RING_BUFFER
650 help
651 Run a simple self test on the ring buffer on boot up. Late in the
652 kernel boot sequence, the test will start that kicks off
653 a thread per cpu. Each thread will write various size events
654 into the ring buffer. Another thread is created to send IPIs
655 to each of the threads, where the IPI handler will also write
656 to the ring buffer, to test/stress the nesting ability.
657 If any anomalies are discovered, a warning will be displayed
658 and all ring buffers will be disabled.
659
660 The test runs for 10 seconds. This will slow your boot time
661 by at least 10 more seconds.
662
663 At the end of the test, statics and more checks are done.
664 It will output the stats of each per cpu buffer. What
665 was written, the sizes, what was read, what was lost, and
666 other similar details.
667
668 If unsure, say N
669
670config TRACE_EVAL_MAP_FILE
671 bool "Show eval mappings for trace events"
672 depends on TRACING
673 help
674 The "print fmt" of the trace events will show the enum/sizeof names
675 instead of their values. This can cause problems for user space tools
676 that use this string to parse the raw data as user space does not know
677 how to convert the string to its value.
678
679 To fix this, there's a special macro in the kernel that can be used
680 to convert an enum/sizeof into its value. If this macro is used, then
681 the print fmt strings will be converted to their values.
682
683 If something does not get converted properly, this option can be
684 used to show what enums/sizeof the kernel tried to convert.
685
686 This option is for debugging the conversions. A file is created
687 in the tracing directory called "eval_map" that will show the
688 names matched with their values and what trace event system they
689 belong too.
690
691 Normally, the mapping of the strings to values will be freed after
692 boot up or module load. With this option, they will not be freed, as
693 they are needed for the "eval_map" file. Enabling this option will
694 increase the memory footprint of the running kernel.
695
696 If unsure, say N
697
698config TRACING_EVENTS_GPIO
699 bool "Trace gpio events"
700 depends on GPIOLIB
701 default y
702 help
703 Enable tracing events for gpio subsystem
704
705endif
706
707endif
708
709
