Root/kernel/trace/Kconfig

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_FTRACE_MCOUNT_RECORD
43    bool
44    help
45      See Documentation/trace/ftrace-design.txt
46
47config HAVE_SYSCALL_TRACEPOINTS
48    bool
49    help
50      See Documentation/trace/ftrace-design.txt
51
52config HAVE_C_RECORDMCOUNT
53    bool
54    help
55      C version of recordmcount available?
56
57config TRACER_MAX_TRACE
58    bool
59
60config RING_BUFFER
61    bool
62
63config FTRACE_NMI_ENTER
64       bool
65       depends on HAVE_FTRACE_NMI_ENTER
66       default y
67
68config EVENT_TRACING
69    select CONTEXT_SWITCH_TRACER
70    bool
71
72config EVENT_POWER_TRACING_DEPRECATED
73    depends on EVENT_TRACING
74    bool "Deprecated power event trace API, to be removed"
75    default y
76    help
77      Provides old power event types:
78      C-state/idle accounting events:
79      power:power_start
80      power:power_end
81      and old cpufreq accounting event:
82      power:power_frequency
83      This is for userspace compatibility
84      and will vanish after 5 kernel iterations,
85      namely 2.6.41.
86
87config CONTEXT_SWITCH_TRACER
88    bool
89
90config RING_BUFFER_ALLOW_SWAP
91    bool
92    help
93     Allow the use of ring_buffer_swap_cpu.
94     Adds a very slight overhead to tracing when enabled.
95
96# All tracer options should select GENERIC_TRACER. For those options that are
97# enabled by all tracers (context switch and event tracer) they select TRACING.
98# This allows those options to appear when no other tracer is selected. But the
99# options do not appear when something else selects it. We need the two options
100# GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
101# hiding of the automatic options.
102
103config TRACING
104    bool
105    select DEBUG_FS
106    select RING_BUFFER
107    select STACKTRACE if STACKTRACE_SUPPORT
108    select TRACEPOINTS
109    select NOP_TRACER
110    select BINARY_PRINTF
111    select EVENT_TRACING
112
113config GENERIC_TRACER
114    bool
115    select TRACING
116
117#
118# Minimum requirements an architecture has to meet for us to
119# be able to offer generic tracing facilities:
120#
121config TRACING_SUPPORT
122    bool
123    # PPC32 has no irqflags tracing support, but it can use most of the
124    # tracers anyway, they were tested to build and work. Note that new
125    # exceptions to this list aren't welcomed, better implement the
126    # irqflags tracing for your architecture.
127    depends on TRACE_IRQFLAGS_SUPPORT || PPC32
128    depends on STACKTRACE_SUPPORT
129    default y
130
131if TRACING_SUPPORT
132
133menuconfig FTRACE
134    bool "Tracers"
135    default y if DEBUG_KERNEL
136    help
137      Enable the kernel tracing infrastructure.
138
139if FTRACE
140
141config FUNCTION_TRACER
142    bool "Kernel Function Tracer"
143    depends on HAVE_FUNCTION_TRACER
144    select FRAME_POINTER if !ARM_UNWIND && !S390 && !MICROBLAZE
145    select KALLSYMS
146    select GENERIC_TRACER
147    select CONTEXT_SWITCH_TRACER
148    help
149      Enable the kernel to trace every kernel function. This is done
150      by using a compiler feature to insert a small, 5-byte No-Operation
151      instruction at the beginning of every kernel function, which NOP
152      sequence is then dynamically patched into a tracer call when
153      tracing is enabled by the administrator. If it's runtime disabled
154      (the bootup default), then the overhead of the instructions is very
155      small and not measurable even in micro-benchmarks.
156
157config FUNCTION_GRAPH_TRACER
158    bool "Kernel Function Graph Tracer"
159    depends on HAVE_FUNCTION_GRAPH_TRACER
160    depends on FUNCTION_TRACER
161    depends on !X86_32 || !CC_OPTIMIZE_FOR_SIZE
162    default y
163    help
164      Enable the kernel to trace a function at both its return
165      and its entry.
166      Its first purpose is to trace the duration of functions and
167      draw a call graph for each thread with some information like
168      the return value. This is done by setting the current return
169      address on the current task structure into a stack of calls.
170
171
172config IRQSOFF_TRACER
173    bool "Interrupts-off Latency Tracer"
174    default n
175    depends on TRACE_IRQFLAGS_SUPPORT
176    depends on !ARCH_USES_GETTIMEOFFSET
177    select TRACE_IRQFLAGS
178    select GENERIC_TRACER
179    select TRACER_MAX_TRACE
180    select RING_BUFFER_ALLOW_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    help
204      This option measures the time spent in preemption-off critical
205      sections, with microsecond accuracy.
206
207      The default measurement method is a maximum search, which is
208      disabled by default and can be runtime (re-)started
209      via:
210
211          echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
212
213      (Note that kernel size and overhead increase with this option
214      enabled. This option and the irqs-off timing option can be
215      used together or separately.)
216
217config SCHED_TRACER
218    bool "Scheduling Latency Tracer"
219    select GENERIC_TRACER
220    select CONTEXT_SWITCH_TRACER
221    select TRACER_MAX_TRACE
222    help
223      This tracer tracks the latency of the highest priority task
224      to be scheduled in, starting from the point it has woken up.
225
226config ENABLE_DEFAULT_TRACERS
227    bool "Trace process context switches and events"
228    depends on !GENERIC_TRACER
229    select TRACING
230    help
231      This tracer hooks to various trace points in the kernel,
232      allowing the user to pick and choose which trace point they
233      want to trace. It also includes the sched_switch tracer plugin.
234
235config FTRACE_SYSCALLS
236    bool "Trace syscalls"
237    depends on HAVE_SYSCALL_TRACEPOINTS
238    select GENERIC_TRACER
239    select KALLSYMS
240    help
241      Basic tracer to catch the syscall entry and exit events.
242
243config TRACE_BRANCH_PROFILING
244    bool
245    select GENERIC_TRACER
246
247choice
248    prompt "Branch Profiling"
249    default BRANCH_PROFILE_NONE
250    help
251     The branch profiling is a software profiler. It will add hooks
252     into the C conditionals to test which path a branch takes.
253
254     The likely/unlikely profiler only looks at the conditions that
255     are annotated with a likely or unlikely macro.
256
257     The "all branch" profiler will profile every if-statement in the
258     kernel. This profiler will also enable the likely/unlikely
259     profiler.
260
261     Either of the above profilers adds a bit of overhead to the system.
262     If unsure, choose "No branch profiling".
263
264config BRANCH_PROFILE_NONE
265    bool "No branch profiling"
266    help
267      No branch profiling. Branch profiling adds a bit of overhead.
268      Only enable it if you want to analyse the branching behavior.
269      Otherwise keep it disabled.
270
271config PROFILE_ANNOTATED_BRANCHES
272    bool "Trace likely/unlikely profiler"
273    select TRACE_BRANCH_PROFILING
274    help
275      This tracer profiles all the the likely and unlikely macros
276      in the kernel. It will display the results in:
277
278      /sys/kernel/debug/tracing/trace_stat/branch_annotated
279
280      Note: this will add a significant overhead; only turn this
281      on if you need to profile the system's use of these macros.
282
283config PROFILE_ALL_BRANCHES
284    bool "Profile all if conditionals"
285    select TRACE_BRANCH_PROFILING
286    help
287      This tracer profiles all branch conditions. Every if ()
288      taken in the kernel is recorded whether it hit or miss.
289      The results will be displayed in:
290
291      /sys/kernel/debug/tracing/trace_stat/branch_all
292
293      This option also enables the likely/unlikely profiler.
294
295      This configuration, when enabled, will impose a great overhead
296      on the system. This should only be enabled when the system
297      is to be analyzed in much detail.
298endchoice
299
300config TRACING_BRANCHES
301    bool
302    help
303      Selected by tracers that will trace the likely and unlikely
304      conditions. This prevents the tracers themselves from being
305      profiled. Profiling the tracing infrastructure can only happen
306      when the likelys and unlikelys are not being traced.
307
308config BRANCH_TRACER
309    bool "Trace likely/unlikely instances"
310    depends on TRACE_BRANCH_PROFILING
311    select TRACING_BRANCHES
312    help
313      This traces the events of likely and unlikely condition
314      calls in the kernel. The difference between this and the
315      "Trace likely/unlikely profiler" is that this is not a
316      histogram of the callers, but actually places the calling
317      events into a running trace buffer to see when and where the
318      events happened, as well as their results.
319
320      Say N if unsure.
321
322config STACK_TRACER
323    bool "Trace max stack"
324    depends on HAVE_FUNCTION_TRACER
325    select FUNCTION_TRACER
326    select STACKTRACE
327    select KALLSYMS
328    help
329      This special tracer records the maximum stack footprint of the
330      kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
331
332      This tracer works by hooking into every function call that the
333      kernel executes, and keeping a maximum stack depth value and
334      stack-trace saved. If this is configured with DYNAMIC_FTRACE
335      then it will not have any overhead while the stack tracer
336      is disabled.
337
338      To enable the stack tracer on bootup, pass in 'stacktrace'
339      on the kernel command line.
340
341      The stack tracer can also be enabled or disabled via the
342      sysctl kernel.stack_tracer_enabled
343
344      Say N if unsure.
345
346config BLK_DEV_IO_TRACE
347    bool "Support for tracing block IO actions"
348    depends on SYSFS
349    depends on BLOCK
350    select RELAY
351    select DEBUG_FS
352    select TRACEPOINTS
353    select GENERIC_TRACER
354    select STACKTRACE
355    help
356      Say Y here if you want to be able to trace the block layer actions
357      on a given queue. Tracing allows you to see any traffic happening
358      on a block device queue. For more information (and the userspace
359      support tools needed), fetch the blktrace tools from:
360
361      git://git.kernel.dk/blktrace.git
362
363      Tracing also is possible using the ftrace interface, e.g.:
364
365        echo 1 > /sys/block/sda/sda1/trace/enable
366        echo blk > /sys/kernel/debug/tracing/current_tracer
367        cat /sys/kernel/debug/tracing/trace_pipe
368
369      If unsure, say N.
370
371config KPROBE_EVENT
372    depends on KPROBES
373    depends on HAVE_REGS_AND_STACK_ACCESS_API
374    bool "Enable kprobes-based dynamic events"
375    select TRACING
376    default y
377    help
378      This allows the user to add tracing events (similar to tracepoints)
379      on the fly via the ftrace interface. See
380      Documentation/trace/kprobetrace.txt for more details.
381
382      Those events can be inserted wherever kprobes can probe, and record
383      various register and memory values.
384
385      This option is also required by perf-probe subcommand of perf tools.
386      If you want to use perf tools, this option is strongly recommended.
387
388config DYNAMIC_FTRACE
389    bool "enable/disable ftrace tracepoints dynamically"
390    depends on FUNCTION_TRACER
391    depends on HAVE_DYNAMIC_FTRACE
392    default y
393    help
394          This option will modify all the calls to ftrace dynamically
395      (will patch them out of the binary image and replace them
396      with a No-Op instruction) as they are called. A table is
397      created to dynamically enable them again.
398
399      This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
400      otherwise has native performance as long as no tracing is active.
401
402      The changes to the code are done by a kernel thread that
403      wakes up once a second and checks to see if any ftrace calls
404      were made. If so, it runs stop_machine (stops all CPUS)
405      and modifies the code to jump over the call to ftrace.
406
407config FUNCTION_PROFILER
408    bool "Kernel function profiler"
409    depends on FUNCTION_TRACER
410    default n
411    help
412      This option enables the kernel function profiler. A file is created
413      in debugfs called function_profile_enabled which defaults to zero.
414      When a 1 is echoed into this file profiling begins, and when a
415      zero is entered, profiling stops. A "functions" file is created in
416      the trace_stats directory; this file shows the list of functions that
417      have been hit and their counters.
418
419      If in doubt, say N.
420
421config FTRACE_MCOUNT_RECORD
422    def_bool y
423    depends on DYNAMIC_FTRACE
424    depends on HAVE_FTRACE_MCOUNT_RECORD
425
426config FTRACE_SELFTEST
427    bool
428
429config FTRACE_STARTUP_TEST
430    bool "Perform a startup test on ftrace"
431    depends on GENERIC_TRACER
432    select FTRACE_SELFTEST
433    help
434      This option performs a series of startup tests on ftrace. On bootup
435      a series of tests are made to verify that the tracer is
436      functioning properly. It will do tests on all the configured
437      tracers of ftrace.
438
439config EVENT_TRACE_TEST_SYSCALLS
440    bool "Run selftest on syscall events"
441    depends on FTRACE_STARTUP_TEST
442    help
443     This option will also enable testing every syscall event.
444     It only enables the event and disables it and runs various loads
445     with the event enabled. This adds a bit more time for kernel boot
446     up since it runs this on every system call defined.
447
448     TBD - enable a way to actually call the syscalls as we test their
449           events
450
451config MMIOTRACE
452    bool "Memory mapped IO tracing"
453    depends on HAVE_MMIOTRACE_SUPPORT && PCI
454    select GENERIC_TRACER
455    help
456      Mmiotrace traces Memory Mapped I/O access and is meant for
457      debugging and reverse engineering. It is called from the ioremap
458      implementation and works via page faults. Tracing is disabled by
459      default and can be enabled at run-time.
460
461      See Documentation/trace/mmiotrace.txt.
462      If you are not helping to develop drivers, say N.
463
464config MMIOTRACE_TEST
465    tristate "Test module for mmiotrace"
466    depends on MMIOTRACE && m
467    help
468      This is a dumb module for testing mmiotrace. It is very dangerous
469      as it will write garbage to IO memory starting at a given address.
470      However, it should be safe to use on e.g. unused portion of VRAM.
471
472      Say N, unless you absolutely know what you are doing.
473
474config RING_BUFFER_BENCHMARK
475    tristate "Ring buffer benchmark stress tester"
476    depends on RING_BUFFER
477    help
478      This option creates a test to stress the ring buffer and benchmark it.
479      It creates its own ring buffer such that it will not interfere with
480      any other users of the ring buffer (such as ftrace). It then creates
481      a producer and consumer that will run for 10 seconds and sleep for
482      10 seconds. Each interval it will print out the number of events
483      it recorded and give a rough estimate of how long each iteration took.
484
485      It does not disable interrupts or raise its priority, so it may be
486      affected by processes that are running.
487
488      If unsure, say N.
489
490endif # FTRACE
491
492endif # TRACING_SUPPORT
493
494

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