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