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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_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# All tracer options should select GENERIC_TRACER. For those options that are
90# enabled by all tracers (context switch and event tracer) they select TRACING.
91# This allows those options to appear when no other tracer is selected. But the
92# options do not appear when something else selects it. We need the two options
93# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
94# hiding of the automatic options.
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# Minimum requirements an architecture has to meet for us to
113# be able to offer generic tracing facilities:
114#
115config TRACING_SUPPORT
116 bool
117 # PPC32 has no irqflags tracing support, but it can use most of the
118 # tracers anyway, they were tested to build and work. Note that new
119 # exceptions to this list aren't welcomed, better implement the
120 # irqflags tracing for your architecture.
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 BPF_EVENTS
436 depends on BPF_SYSCALL
437 depends on (KPROBE_EVENT || UPROBE_EVENT) && PERF_EVENTS
438 bool
439 default y
440 help
441 This allows the user to attach BPF programs to kprobe events.
442
443config PROBE_EVENTS
444 def_bool n
445
446config DYNAMIC_FTRACE
447 bool "enable/disable function tracing dynamically"
448 depends on FUNCTION_TRACER
449 depends on HAVE_DYNAMIC_FTRACE
450 default y
451 help
452 This option will modify all the calls to function tracing
453 dynamically (will patch them out of the binary image and
454 replace them with a No-Op instruction) on boot up. During
455 compile time, a table is made of all the locations that ftrace
456 can function trace, and this table is linked into the kernel
457 image. When this is enabled, functions can be individually
458 enabled, and the functions not enabled will not affect
459 performance of the system.
460
461 See the files in /sys/kernel/debug/tracing:
462 available_filter_functions
463 set_ftrace_filter
464 set_ftrace_notrace
465
466 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
467 otherwise has native performance as long as no tracing is active.
468
469config DYNAMIC_FTRACE_WITH_REGS
470 def_bool y
471 depends on DYNAMIC_FTRACE
472 depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
473
474config FUNCTION_PROFILER
475 bool "Kernel function profiler"
476 depends on FUNCTION_TRACER
477 default n
478 help
479 This option enables the kernel function profiler. A file is created
480 in debugfs called function_profile_enabled which defaults to zero.
481 When a 1 is echoed into this file profiling begins, and when a
482 zero is entered, profiling stops. A "functions" file is created in
483 the trace_stats directory; this file shows the list of functions that
484 have been hit and their counters.
485
486 If in doubt, say N.
487
488config FTRACE_MCOUNT_RECORD
489 def_bool y
490 depends on DYNAMIC_FTRACE
491 depends on HAVE_FTRACE_MCOUNT_RECORD
492
493config FTRACE_SELFTEST
494 bool
495
496config FTRACE_STARTUP_TEST
497 bool "Perform a startup test on ftrace"
498 depends on GENERIC_TRACER
499 select FTRACE_SELFTEST
500 help
501 This option performs a series of startup tests on ftrace. On bootup
502 a series of tests are made to verify that the tracer is
503 functioning properly. It will do tests on all the configured
504 tracers of ftrace.
505
506config EVENT_TRACE_TEST_SYSCALLS
507 bool "Run selftest on syscall events"
508 depends on FTRACE_STARTUP_TEST
509 help
510 This option will also enable testing every syscall event.
511 It only enables the event and disables it and runs various loads
512 with the event enabled. This adds a bit more time for kernel boot
513 up since it runs this on every system call defined.
514
515 TBD - enable a way to actually call the syscalls as we test their
516 events
517
518config MMIOTRACE
519 bool "Memory mapped IO tracing"
520 depends on HAVE_MMIOTRACE_SUPPORT && PCI
521 select GENERIC_TRACER
522 help
523 Mmiotrace traces Memory Mapped I/O access and is meant for
524 debugging and reverse engineering. It is called from the ioremap
525 implementation and works via page faults. Tracing is disabled by
526 default and can be enabled at run-time.
527
528 See Documentation/trace/mmiotrace.txt.
529 If you are not helping to develop drivers, say N.
530
531config MMIOTRACE_TEST
532 tristate "Test module for mmiotrace"
533 depends on MMIOTRACE && m
534 help
535 This is a dumb module for testing mmiotrace. It is very dangerous
536 as it will write garbage to IO memory starting at a given address.
537 However, it should be safe to use on e.g. unused portion of VRAM.
538
539 Say N, unless you absolutely know what you are doing.
540
541config TRACEPOINT_BENCHMARK
542 bool "Add tracepoint that benchmarks tracepoints"
543 help
544 This option creates the tracepoint "benchmark:benchmark_event".
545 When the tracepoint is enabled, it kicks off a kernel thread that
546 goes into an infinite loop (calling cond_sched() to let other tasks
547 run), and calls the tracepoint. Each iteration will record the time
548 it took to write to the tracepoint and the next iteration that
549 data will be passed to the tracepoint itself. That is, the tracepoint
550 will report the time it took to do the previous tracepoint.
551 The string written to the tracepoint is a static string of 128 bytes
552 to keep the time the same. The initial string is simply a write of
553 "START". The second string records the cold cache time of the first
554 write which is not added to the rest of the calculations.
555
556 As it is a tight loop, it benchmarks as hot cache. That's fine because
557 we care most about hot paths that are probably in cache already.
558
559 An example of the output:
560
561 START
562 first=3672 [COLD CACHED]
563 last=632 first=3672 max=632 min=632 avg=316 std=446 std^2=199712
564 last=278 first=3672 max=632 min=278 avg=303 std=316 std^2=100337
565 last=277 first=3672 max=632 min=277 avg=296 std=258 std^2=67064
566 last=273 first=3672 max=632 min=273 avg=292 std=224 std^2=50411
567 last=273 first=3672 max=632 min=273 avg=288 std=200 std^2=40389
568 last=281 first=3672 max=632 min=273 avg=287 std=183 std^2=33666
569
570
571config RING_BUFFER_BENCHMARK
572 tristate "Ring buffer benchmark stress tester"
573 depends on RING_BUFFER
574 help
575 This option creates a test to stress the ring buffer and benchmark it.
576 It creates its own ring buffer such that it will not interfere with
577 any other users of the ring buffer (such as ftrace). It then creates
578 a producer and consumer that will run for 10 seconds and sleep for
579 10 seconds. Each interval it will print out the number of events
580 it recorded and give a rough estimate of how long each iteration took.
581
582 It does not disable interrupts or raise its priority, so it may be
583 affected by processes that are running.
584
585 If unsure, say N.
586
587config RING_BUFFER_STARTUP_TEST
588 bool "Ring buffer startup self test"
589 depends on RING_BUFFER
590 help
591 Run a simple self test on the ring buffer on boot up. Late in the
592 kernel boot sequence, the test will start that kicks off
593 a thread per cpu. Each thread will write various size events
594 into the ring buffer. Another thread is created to send IPIs
595 to each of the threads, where the IPI handler will also write
596 to the ring buffer, to test/stress the nesting ability.
597 If any anomalies are discovered, a warning will be displayed
598 and all ring buffers will be disabled.
599
600 The test runs for 10 seconds. This will slow your boot time
601 by at least 10 more seconds.
602
603 At the end of the test, statics and more checks are done.
604 It will output the stats of each per cpu buffer. What
605 was written, the sizes, what was read, what was lost, and
606 other similar details.
607
608 If unsure, say N
609
610config TRACE_ENUM_MAP_FILE
611 bool "Show enum mappings for trace events"
612 depends on TRACING
613 help
614 The "print fmt" of the trace events will show the enum names instead
615 of their values. This can cause problems for user space tools that
616 use this string to parse the raw data as user space does not know
617 how to convert the string to its value.
618
619 To fix this, there's a special macro in the kernel that can be used
620 to convert the enum into its value. If this macro is used, then the
621 print fmt strings will have the enums converted to their values.
622
623 If something does not get converted properly, this option can be
624 used to show what enums the kernel tried to convert.
625
626 This option is for debugging the enum conversions. A file is created
627 in the tracing directory called "enum_map" that will show the enum
628 names matched with their values and what trace event system they
629 belong too.
630
631 Normally, the mapping of the strings to values will be freed after
632 boot up or module load. With this option, they will not be freed, as
633 they are needed for the "enum_map" file. Enabling this option will
634 increase the memory footprint of the running kernel.
635
636 If unsure, say N
637
638config TRACING_EVENTS_GPIO
639 bool "Trace gpio events"
640 depends on GPIOLIB
641 default y
642 help
643 Enable tracing events for gpio subsystem
644
645endif # FTRACE
646
647endif # TRACING_SUPPORT
648
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