Version:  2.6.34 2.6.35 2.6.36 2.6.37 2.6.38 2.6.39 3.0 3.1 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

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_FUNCTION_TRACE_MCOUNT_TEST
 33         bool
 34         help
 35           See Documentation/trace/ftrace-design.txt
 36 
 37 config HAVE_DYNAMIC_FTRACE
 38         bool
 39         help
 40           See Documentation/trace/ftrace-design.txt
 41 
 42 config HAVE_DYNAMIC_FTRACE_WITH_REGS
 43         bool
 44 
 45 config HAVE_FTRACE_MCOUNT_RECORD
 46         bool
 47         help
 48           See Documentation/trace/ftrace-design.txt
 49 
 50 config HAVE_SYSCALL_TRACEPOINTS
 51         bool
 52         help
 53           See Documentation/trace/ftrace-design.txt
 54 
 55 config HAVE_FENTRY
 56         bool
 57         help
 58           Arch supports the gcc options -pg with -mfentry
 59 
 60 config HAVE_C_RECORDMCOUNT
 61         bool
 62         help
 63           C version of recordmcount available?
 64 
 65 config TRACER_MAX_TRACE
 66         bool
 67 
 68 config TRACE_CLOCK
 69         bool
 70 
 71 config RING_BUFFER
 72         bool
 73         select TRACE_CLOCK
 74         select IRQ_WORK
 75 
 76 config FTRACE_NMI_ENTER
 77        bool
 78        depends on HAVE_FTRACE_NMI_ENTER
 79        default y
 80 
 81 config EVENT_TRACING
 82         select CONTEXT_SWITCH_TRACER
 83         bool
 84 
 85 config CONTEXT_SWITCH_TRACER
 86         bool
 87 
 88 config 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 
101 config 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 
112 config 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 #
120 config 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 
130 if TRACING_SUPPORT
131 
132 menuconfig FTRACE
133         bool "Tracers"
134         default y if DEBUG_KERNEL
135         help
136           Enable the kernel tracing infrastructure.
137 
138 if FTRACE
139 
140 config 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 
155 config 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 
170 config 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 
195 config 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 
219 config 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 
229 config 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 
238 config 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 
246 config 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 
256 config 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 
277 config TRACE_BRANCH_PROFILING
278         bool
279         select GENERIC_TRACER
280 
281 choice
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 
298 config 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 
305 config 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 
317 config 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.
332 endchoice
333 
334 config 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 
342 config 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 
356 config 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 
380 config 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 
405 config 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 
423 config UPROBE_EVENT
424         bool "Enable uprobes-based dynamic events"
425         depends on ARCH_SUPPORTS_UPROBES
426         depends on MMU
427         select UPROBES
428         select PROBE_EVENTS
429         select TRACING
430         default n
431         help
432           This allows the user to add tracing events on top of userspace
433           dynamic events (similar to tracepoints) on the fly via the trace
434           events interface. Those events can be inserted wherever uprobes
435           can probe, and record various registers.
436           This option is required if you plan to use perf-probe subcommand
437           of perf tools on user space applications.
438 
439 config PROBE_EVENTS
440         def_bool n
441 
442 config DYNAMIC_FTRACE
443         bool "enable/disable function tracing dynamically"
444         depends on FUNCTION_TRACER
445         depends on HAVE_DYNAMIC_FTRACE
446         default y
447         help
448           This option will modify all the calls to function tracing
449           dynamically (will patch them out of the binary image and
450           replace them with a No-Op instruction) on boot up. During
451           compile time, a table is made of all the locations that ftrace
452           can function trace, and this table is linked into the kernel
453           image. When this is enabled, functions can be individually
454           enabled, and the functions not enabled will not affect
455           performance of the system.
456 
457           See the files in /sys/kernel/debug/tracing:
458             available_filter_functions
459             set_ftrace_filter
460             set_ftrace_notrace
461 
462           This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
463           otherwise has native performance as long as no tracing is active.
464 
465 config DYNAMIC_FTRACE_WITH_REGS
466         def_bool y
467         depends on DYNAMIC_FTRACE
468         depends on HAVE_DYNAMIC_FTRACE_WITH_REGS
469 
470 config FUNCTION_PROFILER
471         bool "Kernel function profiler"
472         depends on FUNCTION_TRACER
473         default n
474         help
475           This option enables the kernel function profiler. A file is created
476           in debugfs called function_profile_enabled which defaults to zero.
477           When a 1 is echoed into this file profiling begins, and when a
478           zero is entered, profiling stops. A "functions" file is created in
479           the trace_stats directory; this file shows the list of functions that
480           have been hit and their counters.
481 
482           If in doubt, say N.
483 
484 config FTRACE_MCOUNT_RECORD
485         def_bool y
486         depends on DYNAMIC_FTRACE
487         depends on HAVE_FTRACE_MCOUNT_RECORD
488 
489 config FTRACE_SELFTEST
490         bool
491 
492 config FTRACE_STARTUP_TEST
493         bool "Perform a startup test on ftrace"
494         depends on GENERIC_TRACER
495         select FTRACE_SELFTEST
496         help
497           This option performs a series of startup tests on ftrace. On bootup
498           a series of tests are made to verify that the tracer is
499           functioning properly. It will do tests on all the configured
500           tracers of ftrace.
501 
502 config EVENT_TRACE_TEST_SYSCALLS
503         bool "Run selftest on syscall events"
504         depends on FTRACE_STARTUP_TEST
505         help
506          This option will also enable testing every syscall event.
507          It only enables the event and disables it and runs various loads
508          with the event enabled. This adds a bit more time for kernel boot
509          up since it runs this on every system call defined.
510 
511          TBD - enable a way to actually call the syscalls as we test their
512                events
513 
514 config MMIOTRACE
515         bool "Memory mapped IO tracing"
516         depends on HAVE_MMIOTRACE_SUPPORT && PCI
517         select GENERIC_TRACER
518         help
519           Mmiotrace traces Memory Mapped I/O access and is meant for
520           debugging and reverse engineering. It is called from the ioremap
521           implementation and works via page faults. Tracing is disabled by
522           default and can be enabled at run-time.
523 
524           See Documentation/trace/mmiotrace.txt.
525           If you are not helping to develop drivers, say N.
526 
527 config MMIOTRACE_TEST
528         tristate "Test module for mmiotrace"
529         depends on MMIOTRACE && m
530         help
531           This is a dumb module for testing mmiotrace. It is very dangerous
532           as it will write garbage to IO memory starting at a given address.
533           However, it should be safe to use on e.g. unused portion of VRAM.
534 
535           Say N, unless you absolutely know what you are doing.
536 
537 config RING_BUFFER_BENCHMARK
538         tristate "Ring buffer benchmark stress tester"
539         depends on RING_BUFFER
540         help
541           This option creates a test to stress the ring buffer and benchmark it.
542           It creates its own ring buffer such that it will not interfere with
543           any other users of the ring buffer (such as ftrace). It then creates
544           a producer and consumer that will run for 10 seconds and sleep for
545           10 seconds. Each interval it will print out the number of events
546           it recorded and give a rough estimate of how long each iteration took.
547 
548           It does not disable interrupts or raise its priority, so it may be
549           affected by processes that are running.
550 
551           If unsure, say N.
552 
553 config RING_BUFFER_STARTUP_TEST
554        bool "Ring buffer startup self test"
555        depends on RING_BUFFER
556        help
557          Run a simple self test on the ring buffer on boot up. Late in the
558          kernel boot sequence, the test will start that kicks off
559          a thread per cpu. Each thread will write various size events
560          into the ring buffer. Another thread is created to send IPIs
561          to each of the threads, where the IPI handler will also write
562          to the ring buffer, to test/stress the nesting ability.
563          If any anomalies are discovered, a warning will be displayed
564          and all ring buffers will be disabled.
565 
566          The test runs for 10 seconds. This will slow your boot time
567          by at least 10 more seconds.
568 
569          At the end of the test, statics and more checks are done.
570          It will output the stats of each per cpu buffer. What
571          was written, the sizes, what was read, what was lost, and
572          other similar details.
573 
574          If unsure, say N
575 
576 endif # FTRACE
577 
578 endif # TRACING_SUPPORT
579 

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