2 # Architectures that offer an FUNCTION_TRACER implementation should
3 # select HAVE_FUNCTION_TRACER:
6 config USER_STACKTRACE_SUPPORT
12 config HAVE_FTRACE_NMI_ENTER
15 config HAVE_FUNCTION_TRACER
18 config HAVE_FUNCTION_GRAPH_TRACER
21 config HAVE_FUNCTION_TRACE_MCOUNT_TEST
24 This gets selected when the arch tests the function_trace_stop
25 variable at the mcount call site. Otherwise, this variable
26 is tested by the called function.
28 config HAVE_DYNAMIC_FTRACE
31 config HAVE_FTRACE_MCOUNT_RECORD
34 config HAVE_HW_BRANCH_TRACER
37 config HAVE_FTRACE_SYSCALLS
40 config TRACER_MAX_TRACE
46 config FTRACE_NMI_ENTER
48 depends on HAVE_FTRACE_NMI_ENTER
52 select CONTEXT_SWITCH_TRACER
55 config CONTEXT_SWITCH_TRACER
59 # All tracer options should select GENERIC_TRACER. For those options that are
60 # enabled by all tracers (context switch and event tracer) they select TRACING.
61 # This allows those options to appear when no other tracer is selected. But the
62 # options do not appear when something else selects it. We need the two options
63 # GENERIC_TRACER and TRACING to avoid circular dependencies to accomplish the
64 # hidding of the automatic options options.
70 select STACKTRACE if STACKTRACE_SUPPORT
81 # Minimum requirements an architecture has to meet for us to
82 # be able to offer generic tracing facilities:
84 config TRACING_SUPPORT
86 # PPC32 has no irqflags tracing support, but it can use most of the
87 # tracers anyway, they were tested to build and work. Note that new
88 # exceptions to this list aren't welcomed, better implement the
89 # irqflags tracing for your architecture.
90 depends on TRACE_IRQFLAGS_SUPPORT || PPC32
91 depends on STACKTRACE_SUPPORT
98 default y if DEBUG_KERNEL
100 Enable the kernel tracing infrastructure.
104 config FUNCTION_TRACER
105 bool "Kernel Function Tracer"
106 depends on HAVE_FUNCTION_TRACER
109 select GENERIC_TRACER
110 select CONTEXT_SWITCH_TRACER
112 Enable the kernel to trace every kernel function. This is done
113 by using a compiler feature to insert a small, 5-byte No-Operation
114 instruction to the beginning of every kernel function, which NOP
115 sequence is then dynamically patched into a tracer call when
116 tracing is enabled by the administrator. If it's runtime disabled
117 (the bootup default), then the overhead of the instructions is very
118 small and not measurable even in micro-benchmarks.
120 config FUNCTION_GRAPH_TRACER
121 bool "Kernel Function Graph Tracer"
122 depends on HAVE_FUNCTION_GRAPH_TRACER
123 depends on FUNCTION_TRACER
126 Enable the kernel to trace a function at both its return
128 Its first purpose is to trace the duration of functions and
129 draw a call graph for each thread with some information like
130 the return value. This is done by setting the current return
131 address on the current task structure into a stack of calls.
134 config IRQSOFF_TRACER
135 bool "Interrupts-off Latency Tracer"
137 depends on TRACE_IRQFLAGS_SUPPORT
138 depends on GENERIC_TIME
139 select TRACE_IRQFLAGS
140 select GENERIC_TRACER
141 select TRACER_MAX_TRACE
143 This option measures the time spent in irqs-off critical
144 sections, with microsecond accuracy.
146 The default measurement method is a maximum search, which is
147 disabled by default and can be runtime (re-)started
150 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
152 (Note that kernel size and overhead increases with this option
153 enabled. This option and the preempt-off timing option can be
154 used together or separately.)
156 config PREEMPT_TRACER
157 bool "Preemption-off Latency Tracer"
159 depends on GENERIC_TIME
161 select GENERIC_TRACER
162 select TRACER_MAX_TRACE
164 This option measures the time spent in preemption off critical
165 sections, with microsecond accuracy.
167 The default measurement method is a maximum search, which is
168 disabled by default and can be runtime (re-)started
171 echo 0 > /sys/kernel/debug/tracing/tracing_max_latency
173 (Note that kernel size and overhead increases with this option
174 enabled. This option and the irqs-off timing option can be
175 used together or separately.)
177 config SYSPROF_TRACER
178 bool "Sysprof Tracer"
180 select GENERIC_TRACER
181 select CONTEXT_SWITCH_TRACER
183 This tracer provides the trace needed by the 'Sysprof' userspace
187 bool "Scheduling Latency Tracer"
188 select GENERIC_TRACER
189 select CONTEXT_SWITCH_TRACER
190 select TRACER_MAX_TRACE
192 This tracer tracks the latency of the highest priority task
193 to be scheduled in, starting from the point it has woken up.
195 config ENABLE_DEFAULT_TRACERS
196 bool "Trace process context switches and events"
197 depends on !GENERIC_TRACER
200 This tracer hooks to various trace points in the kernel
201 allowing the user to pick and choose which trace point they
202 want to trace. It also includes the sched_switch tracer plugin.
204 config FTRACE_SYSCALLS
205 bool "Trace syscalls"
206 depends on HAVE_FTRACE_SYSCALLS
207 select GENERIC_TRACER
210 Basic tracer to catch the syscall entry and exit events.
213 bool "Trace boot initcalls"
214 select GENERIC_TRACER
215 select CONTEXT_SWITCH_TRACER
217 This tracer helps developers to optimize boot times: it records
218 the timings of the initcalls and traces key events and the identity
219 of tasks that can cause boot delays, such as context-switches.
221 Its aim is to be parsed by the /scripts/bootgraph.pl tool to
222 produce pretty graphics about boot inefficiencies, giving a visual
223 representation of the delays during initcalls - but the raw
224 /debug/tracing/trace text output is readable too.
226 You must pass in ftrace=initcall to the kernel command line
227 to enable this on bootup.
229 config TRACE_BRANCH_PROFILING
231 select GENERIC_TRACER
234 prompt "Branch Profiling"
235 default BRANCH_PROFILE_NONE
237 The branch profiling is a software profiler. It will add hooks
238 into the C conditionals to test which path a branch takes.
240 The likely/unlikely profiler only looks at the conditions that
241 are annotated with a likely or unlikely macro.
243 The "all branch" profiler will profile every if statement in the
244 kernel. This profiler will also enable the likely/unlikely
247 Either of the above profilers add a bit of overhead to the system.
248 If unsure choose "No branch profiling".
250 config BRANCH_PROFILE_NONE
251 bool "No branch profiling"
253 No branch profiling. Branch profiling adds a bit of overhead.
254 Only enable it if you want to analyse the branching behavior.
255 Otherwise keep it disabled.
257 config PROFILE_ANNOTATED_BRANCHES
258 bool "Trace likely/unlikely profiler"
259 select TRACE_BRANCH_PROFILING
261 This tracer profiles all the the likely and unlikely macros
262 in the kernel. It will display the results in:
264 /sys/kernel/debug/tracing/profile_annotated_branch
266 Note: this will add a significant overhead, only turn this
267 on if you need to profile the system's use of these macros.
269 config PROFILE_ALL_BRANCHES
270 bool "Profile all if conditionals"
271 select TRACE_BRANCH_PROFILING
273 This tracer profiles all branch conditions. Every if ()
274 taken in the kernel is recorded whether it hit or miss.
275 The results will be displayed in:
277 /sys/kernel/debug/tracing/profile_branch
279 This option also enables the likely/unlikely profiler.
281 This configuration, when enabled, will impose a great overhead
282 on the system. This should only be enabled when the system
286 config TRACING_BRANCHES
289 Selected by tracers that will trace the likely and unlikely
290 conditions. This prevents the tracers themselves from being
291 profiled. Profiling the tracing infrastructure can only happen
292 when the likelys and unlikelys are not being traced.
295 bool "Trace likely/unlikely instances"
296 depends on TRACE_BRANCH_PROFILING
297 select TRACING_BRANCHES
299 This traces the events of likely and unlikely condition
300 calls in the kernel. The difference between this and the
301 "Trace likely/unlikely profiler" is that this is not a
302 histogram of the callers, but actually places the calling
303 events into a running trace buffer to see when and where the
304 events happened, as well as their results.
309 bool "Trace power consumption behavior"
311 select GENERIC_TRACER
313 This tracer helps developers to analyze and optimize the kernels
314 power management decisions, specifically the C-state and P-state
318 bool "Trace read and write access on kernel memory locations"
319 depends on HAVE_HW_BREAKPOINT
322 This tracer helps find read and write operations on any given kernel
323 symbol i.e. /proc/kallsyms.
325 config PROFILE_KSYM_TRACER
326 bool "Profile all kernel memory accesses on 'watched' variables"
327 depends on KSYM_TRACER
329 This tracer profiles kernel accesses on variables watched through the
330 ksym tracer ftrace plugin. Depending upon the hardware, all read
331 and write operations on kernel variables can be monitored for
334 The results will be displayed in:
335 /debugfs/tracing/profile_ksym
340 bool "Trace max stack"
341 depends on HAVE_FUNCTION_TRACER
342 select FUNCTION_TRACER
346 This special tracer records the maximum stack footprint of the
347 kernel and displays it in /sys/kernel/debug/tracing/stack_trace.
349 This tracer works by hooking into every function call that the
350 kernel executes, and keeping a maximum stack depth value and
351 stack-trace saved. If this is configured with DYNAMIC_FTRACE
352 then it will not have any overhead while the stack tracer
355 To enable the stack tracer on bootup, pass in 'stacktrace'
356 on the kernel command line.
358 The stack tracer can also be enabled or disabled via the
359 sysctl kernel.stack_tracer_enabled
363 config HW_BRANCH_TRACER
364 depends on HAVE_HW_BRANCH_TRACER
365 bool "Trace hw branches"
366 select GENERIC_TRACER
368 This tracer records all branches on the system in a circular
369 buffer giving access to the last N branches for each cpu.
372 bool "Trace SLAB allocations"
373 select GENERIC_TRACER
375 kmemtrace provides tracing for slab allocator functions, such as
376 kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
377 data is then fed to the userspace application in order to analyse
378 allocation hotspots, internal fragmentation and so on, making it
379 possible to see how well an allocator performs, as well as debug
380 and profile kernel code.
382 This requires an userspace application to use. See
383 Documentation/trace/kmemtrace.txt for more information.
385 Saying Y will make the kernel somewhat larger and slower. However,
386 if you disable kmemtrace at run-time or boot-time, the performance
387 impact is minimal (depending on the arch the kernel is built for).
391 config WORKQUEUE_TRACER
392 bool "Trace workqueues"
393 select GENERIC_TRACER
395 The workqueue tracer provides some statistical informations
396 about each cpu workqueue thread such as the number of the
397 works inserted and executed since their creation. It can help
398 to evaluate the amount of work each of them have to perform.
399 For example it can help a developer to decide whether he should
400 choose a per cpu workqueue instead of a singlethreaded one.
402 config BLK_DEV_IO_TRACE
403 bool "Support for tracing block io actions"
409 select GENERIC_TRACER
412 Say Y here if you want to be able to trace the block layer actions
413 on a given queue. Tracing allows you to see any traffic happening
414 on a block device queue. For more information (and the userspace
415 support tools needed), fetch the blktrace tools from:
417 git://git.kernel.dk/blktrace.git
419 Tracing also is possible using the ftrace interface, e.g.:
421 echo 1 > /sys/block/sda/sda1/trace/enable
422 echo blk > /sys/kernel/debug/tracing/current_tracer
423 cat /sys/kernel/debug/tracing/trace_pipe
427 config DYNAMIC_FTRACE
428 bool "enable/disable ftrace tracepoints dynamically"
429 depends on FUNCTION_TRACER
430 depends on HAVE_DYNAMIC_FTRACE
433 This option will modify all the calls to ftrace dynamically
434 (will patch them out of the binary image and replaces them
435 with a No-Op instruction) as they are called. A table is
436 created to dynamically enable them again.
438 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
439 has native performance as long as no tracing is active.
441 The changes to the code are done by a kernel thread that
442 wakes up once a second and checks to see if any ftrace calls
443 were made. If so, it runs stop_machine (stops all CPUS)
444 and modifies the code to jump over the call to ftrace.
446 config FUNCTION_PROFILER
447 bool "Kernel function profiler"
448 depends on FUNCTION_TRACER
451 This option enables the kernel function profiler. A file is created
452 in debugfs called function_profile_enabled which defaults to zero.
453 When a 1 is echoed into this file profiling begins, and when a
454 zero is entered, profiling stops. A file in the trace_stats
455 directory called functions, that show the list of functions that
456 have been hit and their counters.
460 config FTRACE_MCOUNT_RECORD
462 depends on DYNAMIC_FTRACE
463 depends on HAVE_FTRACE_MCOUNT_RECORD
465 config FTRACE_SELFTEST
468 config FTRACE_STARTUP_TEST
469 bool "Perform a startup test on ftrace"
470 depends on GENERIC_TRACER
471 select FTRACE_SELFTEST
473 This option performs a series of startup tests on ftrace. On bootup
474 a series of tests are made to verify that the tracer is
475 functioning properly. It will do tests on all the configured
479 bool "Memory mapped IO tracing"
480 depends on HAVE_MMIOTRACE_SUPPORT && PCI
481 select GENERIC_TRACER
483 Mmiotrace traces Memory Mapped I/O access and is meant for
484 debugging and reverse engineering. It is called from the ioremap
485 implementation and works via page faults. Tracing is disabled by
486 default and can be enabled at run-time.
488 See Documentation/trace/mmiotrace.txt.
489 If you are not helping to develop drivers, say N.
491 config MMIOTRACE_TEST
492 tristate "Test module for mmiotrace"
493 depends on MMIOTRACE && m
495 This is a dumb module for testing mmiotrace. It is very dangerous
496 as it will write garbage to IO memory starting at a given address.
497 However, it should be safe to use on e.g. unused portion of VRAM.
499 Say N, unless you absolutely know what you are doing.
501 config RING_BUFFER_BENCHMARK
502 tristate "Ring buffer benchmark stress tester"
503 depends on RING_BUFFER
505 This option creates a test to stress the ring buffer and bench mark it.
506 It creates its own ring buffer such that it will not interfer with
507 any other users of the ring buffer (such as ftrace). It then creates
508 a producer and consumer that will run for 10 seconds and sleep for
509 10 seconds. Each interval it will print out the number of events
510 it recorded and give a rough estimate of how long each iteration took.
512 It does not disable interrupts or raise its priority, so it may be
513 affected by processes that are running.
519 endif # TRACING_SUPPORT