Version:  2.0.40 2.2.26 2.4.37 3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10 3.11 3.12 3.13 3.14 3.15 3.16 3.17 3.18

Linux/kernel/trace/Kconfig

  1 #
  2 # Architectures that offer an FUNCTION_TRACER implementation should
  3 #  select HAVE_FUNCTION_TRACER:
  4 #
  5 
  6 config USER_STACKTRACE_SUPPORT
  7         bool
  8 
  9 config NOP_TRACER
 10         bool
 11 
 12 config HAVE_FTRACE_NMI_ENTER
 13         bool
 14         help
 15           See Documentation/trace/ftrace-design.txt
 16 
 17 config HAVE_FUNCTION_TRACER
 18         bool
 19         help
 20           See Documentation/trace/ftrace-design.txt
 21 
 22 config HAVE_FUNCTION_GRAPH_TRACER
 23         bool
 24         help
 25           See Documentation/trace/ftrace-design.txt
 26 
 27 config HAVE_FUNCTION_GRAPH_FP_TEST
 28         bool
 29         help
 30           See Documentation/trace/ftrace-design.txt
 31 
 32 config HAVE_DYNAMIC_FTRACE
 33         bool
 34         help
 35           See Documentation/trace/ftrace-design.txt
 36 
 37 config HAVE_DYNAMIC_FTRACE_WITH_REGS
 38         bool
 39 
 40 config HAVE_FTRACE_MCOUNT_RECORD
 41         bool
 42         help
 43           See Documentation/trace/ftrace-design.txt
 44 
 45 config HAVE_SYSCALL_TRACEPOINTS
 46         bool
 47         help
 48           See Documentation/trace/ftrace-design.txt
 49 
 50 config HAVE_FENTRY
 51         bool
 52         help
 53           Arch supports the gcc options -pg with -mfentry
 54 
 55 config HAVE_C_RECORDMCOUNT
 56         bool
 57         help
 58           C version of recordmcount available?
 59 
 60 config TRACER_MAX_TRACE
 61         bool
 62 
 63 config TRACE_CLOCK
 64         bool
 65 
 66 config RING_BUFFER
 67         bool
 68         select TRACE_CLOCK
 69         select IRQ_WORK
 70 
 71 config FTRACE_NMI_ENTER
 72        bool
 73        depends on HAVE_FTRACE_NMI_ENTER
 74        default y
 75 
 76 config EVENT_TRACING
 77         select CONTEXT_SWITCH_TRACER
 78         bool
 79 
 80 config CONTEXT_SWITCH_TRACER
 81         bool
 82 
 83 config 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 
 96 config 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 
107 config 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 #
115 config 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 
125 if TRACING_SUPPORT
126 
127 menuconfig FTRACE
128         bool "Tracers"
129         default y if DEBUG_KERNEL
130         help
131           Enable the kernel tracing infrastructure.
132 
133 if FTRACE
134 
135 config 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 
150 config 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 
165 config 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 
190 config 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 
214 config 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 
224 config 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 
233 config 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 
241 config 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 
251 config 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 
272 config TRACE_BRANCH_PROFILING
273         bool
274         select GENERIC_TRACER
275 
276 choice
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 
293 config 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 
300 config 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 
312 config 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.
327 endchoice
328 
329 config 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 
337 config 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 
351 config 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 
375 config 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 
400 config 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 
418 config 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 
435 config PROBE_EVENTS
436         def_bool n
437 
438 config 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 
461 config DYNAMIC_FTRACE_WITH_REGS
462         def_bool y
463         depends on DYNAMIC_FTRACE
464         depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
465 
466 config 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 
480 config FTRACE_MCOUNT_RECORD
481         def_bool y
482         depends on DYNAMIC_FTRACE
483         depends on HAVE_FTRACE_MCOUNT_RECORD
484 
485 config FTRACE_SELFTEST
486         bool
487 
488 config 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 
498 config 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 
510 config 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 
523 config 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 
533 config 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 
563 config 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 
579 config 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 
602 endif # FTRACE
603 
604 endif # TRACING_SUPPORT
605 

This page was automatically generated by LXR 0.3.1 (source).  •  Linux is a registered trademark of Linus Torvalds  •  Contact us