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_FUNCTION_GRAPH_FP_TEST
28 bool
29 help
30 See Documentation/trace/ftrace-design.txt
31
32config HAVE_DYNAMIC_FTRACE
33 bool
34 help
35 See Documentation/trace/ftrace-design.txt
36
37config HAVE_DYNAMIC_FTRACE_WITH_REGS
38 bool
39
40config HAVE_FTRACE_MCOUNT_RECORD
41 bool
42 help
43 See Documentation/trace/ftrace-design.txt
44
45config HAVE_SYSCALL_TRACEPOINTS
46 bool
47 help
48 See Documentation/trace/ftrace-design.txt
49
50config HAVE_FENTRY
51 bool
52 help
53 Arch supports the gcc options -pg with -mfentry
54
55config HAVE_C_RECORDMCOUNT
56 bool
57 help
58 C version of recordmcount available?
59
60config TRACER_MAX_TRACE
61 bool
62
63config TRACE_CLOCK
64 bool
65
66config RING_BUFFER
67 bool
68 select TRACE_CLOCK
69 select IRQ_WORK
70
71config FTRACE_NMI_ENTER
72 bool
73 depends on HAVE_FTRACE_NMI_ENTER
74 default y
75
76config EVENT_TRACING
77 select CONTEXT_SWITCH_TRACER
78 bool
79
80config CONTEXT_SWITCH_TRACER
81 bool
82
83config RING_BUFFER_ALLOW_SWAP
84 bool
85 help
86 Allow the use of ring_buffer_swap_cpu.
87 Adds a very slight overhead to tracing when enabled.
88
89
90
91
92
93
94
95
96config TRACING
97 bool
98 select DEBUG_FS
99 select RING_BUFFER
100 select STACKTRACE if STACKTRACE_SUPPORT
101 select TRACEPOINTS
102 select NOP_TRACER
103 select BINARY_PRINTF
104 select EVENT_TRACING
105 select TRACE_CLOCK
106
107config GENERIC_TRACER
108 bool
109 select TRACING
110
111
112
113
114
115config TRACING_SUPPORT
116 bool
117
118
119
120
121 depends on TRACE_IRQFLAGS_SUPPORT || PPC32
122 depends on STACKTRACE_SUPPORT
123 default y
124
125if TRACING_SUPPORT
126
127menuconfig FTRACE
128 bool "Tracers"
129 default y if DEBUG_KERNEL
130 help
131 Enable the kernel tracing infrastructure.
132
133if FTRACE
134
135config FUNCTION_TRACER
136 bool "Kernel Function Tracer"
137 depends on HAVE_FUNCTION_TRACER
138 select KALLSYMS
139 select GENERIC_TRACER
140 select CONTEXT_SWITCH_TRACER
141 help
142 Enable the kernel to trace every kernel function. This is done
143 by using a compiler feature to insert a small, 5-byte No-Operation
144 instruction at the beginning of every kernel function, which NOP
145 sequence is then dynamically patched into a tracer call when
146 tracing is enabled by the administrator. If it's runtime disabled
147 (the bootup default), then the overhead of the instructions is very
148 small and not measurable even in micro-benchmarks.
149
150config FUNCTION_GRAPH_TRACER
151 bool "Kernel Function Graph Tracer"
152 depends on HAVE_FUNCTION_GRAPH_TRACER
153 depends on FUNCTION_TRACER
154 depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
155 default y
156 help
157 Enable the kernel to trace a function at both its return
158 and its entry.
159 Its first purpose is to trace the duration of functions and
160 draw a call graph for each thread with some information like
161 the return value. This is done by setting the current return
162 address on the current task structure into a stack of calls.
163
164
165config IRQSOFF_TRACER
166 bool "Interrupts-off Latency Tracer"
167 default n
168 depends on TRACE_IRQFLAGS_SUPPORT
169 depends on !ARCH_USES_GETTIMEOFFSET
170 select TRACE_IRQFLAGS
171 select GENERIC_TRACER
172 select TRACER_MAX_TRACE
173 select RING_BUFFER_ALLOW_SWAP
174 select TRACER_SNAPSHOT
175 select TRACER_SNAPSHOT_PER_CPU_SWAP
176 help
177 This option measures the time spent in irqs-off critical
178 sections, with microsecond accuracy.
179
180 The default measurement method is a maximum search, which is
181 disabled by default and can be runtime (re-)started
182 via:
183
184 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
185
186 (Note that kernel size and overhead increase with this option
187 enabled. This option and the preempt-off timing option can be
188 used together or separately.)
189
190config PREEMPT_TRACER
191 bool "Preemption-off Latency Tracer"
192 default n
193 depends on !ARCH_USES_GETTIMEOFFSET
194 depends on PREEMPT
195 select GENERIC_TRACER
196 select TRACER_MAX_TRACE
197 select RING_BUFFER_ALLOW_SWAP
198 select TRACER_SNAPSHOT
199 select TRACER_SNAPSHOT_PER_CPU_SWAP
200 help
201 This option measures the time spent in preemption-off critical
202 sections, with microsecond accuracy.
203
204 The default measurement method is a maximum search, which is
205 disabled by default and can be runtime (re-)started
206 via:
207
208 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
209
210 (Note that kernel size and overhead increase with this option
211 enabled. This option and the irqs-off timing option can be
212 used together or separately.)
213
214config SCHED_TRACER
215 bool "Scheduling Latency Tracer"
216 select GENERIC_TRACER
217 select CONTEXT_SWITCH_TRACER
218 select TRACER_MAX_TRACE
219 select TRACER_SNAPSHOT
220 help
221 This tracer tracks the latency of the highest priority task
222 to be scheduled in, starting from the point it has woken up.
223
224config ENABLE_DEFAULT_TRACERS
225 bool "Trace process context switches and events"
226 depends on !GENERIC_TRACER
227 select TRACING
228 help
229 This tracer hooks to various trace points in the kernel,
230 allowing the user to pick and choose which trace point they
231 want to trace. It also includes the sched_switch tracer plugin.
232
233config FTRACE_SYSCALLS
234 bool "Trace syscalls"
235 depends on HAVE_SYSCALL_TRACEPOINTS
236 select GENERIC_TRACER
237 select KALLSYMS
238 help
239 Basic tracer to catch the syscall entry and exit events.
240
241config TRACER_SNAPSHOT
242 bool "Create a snapshot trace buffer"
243 select TRACER_MAX_TRACE
244 help
245 Allow tracing users to take snapshot of the current buffer using the
246 ftrace interface, e.g.:
247
248 echo 1 > /sys/kernel/debug/tracing/snapshot
249 cat snapshot
250
251config TRACER_SNAPSHOT_PER_CPU_SWAP
252 bool "Allow snapshot to swap per CPU"
253 depends on TRACER_SNAPSHOT
254 select RING_BUFFER_ALLOW_SWAP
255 help
256 Allow doing a snapshot of a single CPU buffer instead of a
257 full swap (all buffers). If this is set, then the following is
258 allowed:
259
260 echo 1 > /sys/kernel/debug/tracing/per_cpu/cpu2/snapshot
261
262 After which, only the tracing buffer for CPU 2 was swapped with
263 the main tracing buffer, and the other CPU buffers remain the same.
264
265 When this is enabled, this adds a little more overhead to the
266 trace recording, as it needs to add some checks to synchronize
267 recording with swaps. But this does not affect the performance
268 of the overall system. This is enabled by default when the preempt
269 or irq latency tracers are enabled, as those need to swap as well
270 and already adds the overhead (plus a lot more).
271
272config TRACE_BRANCH_PROFILING
273 bool
274 select GENERIC_TRACER
275
276choice
277 prompt "Branch Profiling"
278 default BRANCH_PROFILE_NONE
279 help
280 The branch profiling is a software profiler. It will add hooks
281 into the C conditionals to test which path a branch takes.
282
283 The likely/unlikely profiler only looks at the conditions that
284 are annotated with a likely or unlikely macro.
285
286 The "all branch" profiler will profile every if-statement in the
287 kernel. This profiler will also enable the likely/unlikely
288 profiler.
289
290 Either of the above profilers adds a bit of overhead to the system.
291 If unsure, choose "No branch profiling".
292
293config BRANCH_PROFILE_NONE
294 bool "No branch profiling"
295 help
296 No branch profiling. Branch profiling adds a bit of overhead.
297 Only enable it if you want to analyse the branching behavior.
298 Otherwise keep it disabled.
299
300config PROFILE_ANNOTATED_BRANCHES
301 bool "Trace likely/unlikely profiler"
302 select TRACE_BRANCH_PROFILING
303 help
304 This tracer profiles all likely and unlikely macros
305 in the kernel. It will display the results in:
306
307 /sys/kernel/debug/tracing/trace_stat/branch_annotated
308
309 Note: this will add a significant overhead; only turn this
310 on if you need to profile the system's use of these macros.
311
312config PROFILE_ALL_BRANCHES
313 bool "Profile all if conditionals"
314 select TRACE_BRANCH_PROFILING
315 help
316 This tracer profiles all branch conditions. Every if ()
317 taken in the kernel is recorded whether it hit or miss.
318 The results will be displayed in:
319
320 /sys/kernel/debug/tracing/trace_stat/branch_all
321
322 This option also enables the likely/unlikely profiler.
323
324 This configuration, when enabled, will impose a great overhead
325 on the system. This should only be enabled when the system
326 is to be analyzed in much detail.
327endchoice
328
329config TRACING_BRANCHES
330 bool
331 help
332 Selected by tracers that will trace the likely and unlikely
333 conditions. This prevents the tracers themselves from being
334 profiled. Profiling the tracing infrastructure can only happen
335 when the likelys and unlikelys are not being traced.
336
337config BRANCH_TRACER
338 bool "Trace likely/unlikely instances"
339 depends on TRACE_BRANCH_PROFILING
340 select TRACING_BRANCHES
341 help
342 This traces the events of likely and unlikely condition
343 calls in the kernel. The difference between this and the
344 "Trace likely/unlikely profiler" is that this is not a
345 histogram of the callers, but actually places the calling
346 events into a running trace buffer to see when and where the
347 events happened, as well as their results.
348
349 Say N if unsure.
350
351config STACK_TRACER
352 bool "Trace max stack"
353 depends on HAVE_FUNCTION_TRACER
354 select FUNCTION_TRACER
355 select STACKTRACE
356 select KALLSYMS
357 help
358 This special tracer records the maximum stack footprint of the
359 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
360
361 This tracer works by hooking into every function call that the
362 kernel executes, and keeping a maximum stack depth value and
363 stack-trace saved. If this is configured with DYNAMIC_FTRACE
364 then it will not have any overhead while the stack tracer
365 is disabled.
366
367 To enable the stack tracer on bootup, pass in 'stacktrace'
368 on the kernel command line.
369
370 The stack tracer can also be enabled or disabled via the
371 sysctl kernel.stack_tracer_enabled
372
373 Say N if unsure.
374
375config BLK_DEV_IO_TRACE
376 bool "Support for tracing block IO actions"
377 depends on SYSFS
378 depends on BLOCK
379 select RELAY
380 select DEBUG_FS
381 select TRACEPOINTS
382 select GENERIC_TRACER
383 select STACKTRACE
384 help
385 Say Y here if you want to be able to trace the block layer actions
386 on a given queue. Tracing allows you to see any traffic happening
387 on a block device queue. For more information (and the userspace
388 support tools needed), fetch the blktrace tools from:
389
390 git://git.kernel.dk/blktrace.git
391
392 Tracing also is possible using the ftrace interface, e.g.:
393
394 echo 1 > /sys/block/sda/sda1/trace/enable
395 echo blk > /sys/kernel/debug/tracing/current_tracer
396 cat /sys/kernel/debug/tracing/trace_pipe
397
398 If unsure, say N.
399
400config KPROBE_EVENT
401 depends on KPROBES
402 depends on HAVE_REGS_AND_STACK_ACCESS_API
403 bool "Enable kprobes-based dynamic events"
404 select TRACING
405 select PROBE_EVENTS
406 default y
407 help
408 This allows the user to add tracing events (similar to tracepoints)
409 on the fly via the ftrace interface. See
410 Documentation/trace/kprobetrace.txt for more details.
411
412 Those events can be inserted wherever kprobes can probe, and record
413 various register and memory values.
414
415 This option is also required by perf-probe subcommand of perf tools.
416 If you want to use perf tools, this option is strongly recommended.
417
418config UPROBE_EVENT
419 bool "Enable uprobes-based dynamic events"
420 depends on ARCH_SUPPORTS_UPROBES
421 depends on MMU
422 depends on PERF_EVENTS
423 select UPROBES
424 select PROBE_EVENTS
425 select TRACING
426 default n
427 help
428 This allows the user to add tracing events on top of userspace
429 dynamic events (similar to tracepoints) on the fly via the trace
430 events interface. Those events can be inserted wherever uprobes
431 can probe, and record various registers.
432 This option is required if you plan to use perf-probe subcommand
433 of perf tools on user space applications.
434
435config PROBE_EVENTS
436 def_bool n
437
438config DYNAMIC_FTRACE
439 bool "enable/disable function tracing dynamically"
440 depends on FUNCTION_TRACER
441 depends on HAVE_DYNAMIC_FTRACE
442 default y
443 help
444 This option will modify all the calls to function tracing
445 dynamically (will patch them out of the binary image and
446 replace them with a No-Op instruction) on boot up. During
447 compile time, a table is made of all the locations that ftrace
448 can function trace, and this table is linked into the kernel
449 image. When this is enabled, functions can be individually
450 enabled, and the functions not enabled will not affect
451 performance of the system.
452
453 See the files in /sys/kernel/debug/tracing:
454 available_filter_functions
455 set_ftrace_filter
456 set_ftrace_notrace
457
458 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
459 otherwise has native performance as long as no tracing is active.
460
461config DYNAMIC_FTRACE_WITH_REGS
462 def_bool y
463 depends on DYNAMIC_FTRACE
464 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
465
466config FUNCTION_PROFILER
467 bool "Kernel function profiler"
468 depends on FUNCTION_TRACER
469 default n
470 help
471 This option enables the kernel function profiler. A file is created
472 in debugfs called function_profile_enabled which defaults to zero.
473 When a 1 is echoed into this file profiling begins, and when a
474 zero is entered, profiling stops. A "functions" file is created in
475 the trace_stats directory; this file shows the list of functions that
476 have been hit and their counters.
477
478 If in doubt, say N.
479
480config FTRACE_MCOUNT_RECORD
481 def_bool y
482 depends on DYNAMIC_FTRACE
483 depends on HAVE_FTRACE_MCOUNT_RECORD
484
485config FTRACE_SELFTEST
486 bool
487
488config FTRACE_STARTUP_TEST
489 bool "Perform a startup test on ftrace"
490 depends on GENERIC_TRACER
491 select FTRACE_SELFTEST
492 help
493 This option performs a series of startup tests on ftrace. On bootup
494 a series of tests are made to verify that the tracer is
495 functioning properly. It will do tests on all the configured
496 tracers of ftrace.
497
498config EVENT_TRACE_TEST_SYSCALLS
499 bool "Run selftest on syscall events"
500 depends on FTRACE_STARTUP_TEST
501 help
502 This option will also enable testing every syscall event.
503 It only enables the event and disables it and runs various loads
504 with the event enabled. This adds a bit more time for kernel boot
505 up since it runs this on every system call defined.
506
507 TBD - enable a way to actually call the syscalls as we test their
508 events
509
510config MMIOTRACE
511 bool "Memory mapped IO tracing"
512 depends on HAVE_MMIOTRACE_SUPPORT && PCI
513 select GENERIC_TRACER
514 help
515 Mmiotrace traces Memory Mapped I/O access and is meant for
516 debugging and reverse engineering. It is called from the ioremap
517 implementation and works via page faults. Tracing is disabled by
518 default and can be enabled at run-time.
519
520 See Documentation/trace/mmiotrace.txt.
521 If you are not helping to develop drivers, say N.
522
523config MMIOTRACE_TEST
524 tristate "Test module for mmiotrace"
525 depends on MMIOTRACE && m
526 help
527 This is a dumb module for testing mmiotrace. It is very dangerous
528 as it will write garbage to IO memory starting at a given address.
529 However, it should be safe to use on e.g. unused portion of VRAM.
530
531 Say N, unless you absolutely know what you are doing.
532
533config TRACEPOINT_BENCHMARK
534 bool "Add tracepoint that benchmarks tracepoints"
535 help
536 This option creates the tracepoint "benchmark:benchmark_event".
537 When the tracepoint is enabled, it kicks off a kernel thread that
538 goes into an infinite loop (calling cond_sched() to let other tasks
539 run), and calls the tracepoint. Each iteration will record the time
540 it took to write to the tracepoint and the next iteration that
541 data will be passed to the tracepoint itself. That is, the tracepoint
542 will report the time it took to do the previous tracepoint.
543 The string written to the tracepoint is a static string of 128 bytes
544 to keep the time the same. The initial string is simply a write of
545 "START". The second string records the cold cache time of the first
546 write which is not added to the rest of the calculations.
547
548 As it is a tight loop, it benchmarks as hot cache. That's fine because
549 we care most about hot paths that are probably in cache already.
550
551 An example of the output:
552
553 START
554 first=3672 [COLD CACHED]
555 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
556 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
557 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
558 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
559 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
560 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
561
562
563config RING_BUFFER_BENCHMARK
564 tristate "Ring buffer benchmark stress tester"
565 depends on RING_BUFFER
566 help
567 This option creates a test to stress the ring buffer and benchmark it.
568 It creates its own ring buffer such that it will not interfere with
569 any other users of the ring buffer (such as ftrace). It then creates
570 a producer and consumer that will run for 10 seconds and sleep for
571 10 seconds. Each interval it will print out the number of events
572 it recorded and give a rough estimate of how long each iteration took.
573
574 It does not disable interrupts or raise its priority, so it may be
575 affected by processes that are running.
576
577 If unsure, say N.
578
579config RING_BUFFER_STARTUP_TEST
580 bool "Ring buffer startup self test"
581 depends on RING_BUFFER
582 help
583 Run a simple self test on the ring buffer on boot up. Late in the
584 kernel boot sequence, the test will start that kicks off
585 a thread per cpu. Each thread will write various size events
586 into the ring buffer. Another thread is created to send IPIs
587 to each of the threads, where the IPI handler will also write
588 to the ring buffer, to test/stress the nesting ability.
589 If any anomalies are discovered, a warning will be displayed
590 and all ring buffers will be disabled.
591
592 The test runs for 10 seconds. This will slow your boot time
593 by at least 10 more seconds.
594
595 At the end of the test, statics and more checks are done.
596 It will output the stats of each per cpu buffer. What
597 was written, the sizes, what was read, what was lost, and
598 other similar details.
599
600 If unsure, say N
601
602endif
603
604endif
605
606
