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
58 select STACKTRACE if STACKTRACE_SUPPORT
65 # Minimum requirements an architecture has to meet for us to
66 # be able to offer generic tracing facilities:
68 config TRACING_SUPPORT
70 # PPC32 has no irqflags tracing support, but it can use most of the
71 # tracers anyway, they were tested to build and work. Note that new
72 # exceptions to this list aren't welcomed, better implement the
73 # irqflags tracing for your architecture.
74 depends on TRACE_IRQFLAGS_SUPPORT || PPC32
75 depends on STACKTRACE_SUPPORT
82 config FUNCTION_TRACER
83 bool "Kernel Function Tracer"
84 depends on HAVE_FUNCTION_TRACER
88 select CONTEXT_SWITCH_TRACER
90 Enable the kernel to trace every kernel function. This is done
91 by using a compiler feature to insert a small, 5-byte No-Operation
92 instruction to the beginning of every kernel function, which NOP
93 sequence is then dynamically patched into a tracer call when
94 tracing is enabled by the administrator. If it's runtime disabled
95 (the bootup default), then the overhead of the instructions is very
96 small and not measurable even in micro-benchmarks.
98 config FUNCTION_GRAPH_TRACER
99 bool "Kernel Function Graph Tracer"
100 depends on HAVE_FUNCTION_GRAPH_TRACER
101 depends on FUNCTION_TRACER
104 Enable the kernel to trace a function at both its return
106 Its first purpose is to trace the duration of functions and
107 draw a call graph for each thread with some information like
108 the return value. This is done by setting the current return
109 address on the current task structure into a stack of calls.
112 config IRQSOFF_TRACER
113 bool "Interrupts-off Latency Tracer"
115 depends on TRACE_IRQFLAGS_SUPPORT
116 depends on GENERIC_TIME
117 select TRACE_IRQFLAGS
119 select TRACER_MAX_TRACE
121 This option measures the time spent in irqs-off critical
122 sections, with microsecond accuracy.
124 The default measurement method is a maximum search, which is
125 disabled by default and can be runtime (re-)started
128 echo 0 > /debugfs/tracing/tracing_max_latency
130 (Note that kernel size and overhead increases with this option
131 enabled. This option and the preempt-off timing option can be
132 used together or separately.)
134 config PREEMPT_TRACER
135 bool "Preemption-off Latency Tracer"
137 depends on GENERIC_TIME
140 select TRACER_MAX_TRACE
142 This option measures the time spent in preemption off critical
143 sections, with microsecond accuracy.
145 The default measurement method is a maximum search, which is
146 disabled by default and can be runtime (re-)started
149 echo 0 > /debugfs/tracing/tracing_max_latency
151 (Note that kernel size and overhead increases with this option
152 enabled. This option and the irqs-off timing option can be
153 used together or separately.)
155 config SYSPROF_TRACER
156 bool "Sysprof Tracer"
159 select CONTEXT_SWITCH_TRACER
161 This tracer provides the trace needed by the 'Sysprof' userspace
165 bool "Scheduling Latency Tracer"
167 select CONTEXT_SWITCH_TRACER
168 select TRACER_MAX_TRACE
170 This tracer tracks the latency of the highest priority task
171 to be scheduled in, starting from the point it has woken up.
173 config CONTEXT_SWITCH_TRACER
174 bool "Trace process context switches"
178 This tracer gets called from the context switch and records
179 all switching of tasks.
182 bool "Trace various events in the kernel"
185 This tracer hooks to various trace points in the kernel
186 allowing the user to pick and choose which trace point they
189 config FTRACE_SYSCALLS
190 bool "Trace syscalls"
191 depends on HAVE_FTRACE_SYSCALLS
195 Basic tracer to catch the syscall entry and exit events.
198 bool "Trace boot initcalls"
200 select CONTEXT_SWITCH_TRACER
202 This tracer helps developers to optimize boot times: it records
203 the timings of the initcalls and traces key events and the identity
204 of tasks that can cause boot delays, such as context-switches.
206 Its aim is to be parsed by the /scripts/bootgraph.pl tool to
207 produce pretty graphics about boot inefficiencies, giving a visual
208 representation of the delays during initcalls - but the raw
209 /debug/tracing/trace text output is readable too.
211 You must pass in ftrace=initcall to the kernel command line
212 to enable this on bootup.
214 config TRACE_BRANCH_PROFILING
215 bool "Trace likely/unlikely profiler"
218 This tracer profiles all the the likely and unlikely macros
219 in the kernel. It will display the results in:
221 /debugfs/tracing/profile_annotated_branch
223 Note: this will add a significant overhead, only turn this
224 on if you need to profile the system's use of these macros.
228 config PROFILE_ALL_BRANCHES
229 bool "Profile all if conditionals"
230 depends on TRACE_BRANCH_PROFILING
232 This tracer profiles all branch conditions. Every if ()
233 taken in the kernel is recorded whether it hit or miss.
234 The results will be displayed in:
236 /debugfs/tracing/profile_branch
238 This configuration, when enabled, will impose a great overhead
239 on the system. This should only be enabled when the system
244 config TRACING_BRANCHES
247 Selected by tracers that will trace the likely and unlikely
248 conditions. This prevents the tracers themselves from being
249 profiled. Profiling the tracing infrastructure can only happen
250 when the likelys and unlikelys are not being traced.
253 bool "Trace likely/unlikely instances"
254 depends on TRACE_BRANCH_PROFILING
255 select TRACING_BRANCHES
257 This traces the events of likely and unlikely condition
258 calls in the kernel. The difference between this and the
259 "Trace likely/unlikely profiler" is that this is not a
260 histogram of the callers, but actually places the calling
261 events into a running trace buffer to see when and where the
262 events happened, as well as their results.
267 bool "Trace power consumption behavior"
271 This tracer helps developers to analyze and optimize the kernels
272 power management decisions, specifically the C-state and P-state
277 bool "Trace max stack"
278 depends on HAVE_FUNCTION_TRACER
279 select FUNCTION_TRACER
283 This special tracer records the maximum stack footprint of the
284 kernel and displays it in debugfs/tracing/stack_trace.
286 This tracer works by hooking into every function call that the
287 kernel executes, and keeping a maximum stack depth value and
288 stack-trace saved. If this is configured with DYNAMIC_FTRACE
289 then it will not have any overhead while the stack tracer
292 To enable the stack tracer on bootup, pass in 'stacktrace'
293 on the kernel command line.
295 The stack tracer can also be enabled or disabled via the
296 sysctl kernel.stack_tracer_enabled
300 config HW_BRANCH_TRACER
301 depends on HAVE_HW_BRANCH_TRACER
302 bool "Trace hw branches"
305 This tracer records all branches on the system in a circular
306 buffer giving access to the last N branches for each cpu.
309 bool "Trace SLAB allocations"
312 kmemtrace provides tracing for slab allocator functions, such as
313 kmalloc, kfree, kmem_cache_alloc, kmem_cache_free etc.. Collected
314 data is then fed to the userspace application in order to analyse
315 allocation hotspots, internal fragmentation and so on, making it
316 possible to see how well an allocator performs, as well as debug
317 and profile kernel code.
319 This requires an userspace application to use. See
320 Documentation/trace/kmemtrace.txt for more information.
322 Saying Y will make the kernel somewhat larger and slower. However,
323 if you disable kmemtrace at run-time or boot-time, the performance
324 impact is minimal (depending on the arch the kernel is built for).
328 config WORKQUEUE_TRACER
329 bool "Trace workqueues"
332 The workqueue tracer provides some statistical informations
333 about each cpu workqueue thread such as the number of the
334 works inserted and executed since their creation. It can help
335 to evaluate the amount of work each of them have to perform.
336 For example it can help a developer to decide whether he should
337 choose a per cpu workqueue instead of a singlethreaded one.
339 config BLK_DEV_IO_TRACE
340 bool "Support for tracing block io actions"
349 Say Y here if you want to be able to trace the block layer actions
350 on a given queue. Tracing allows you to see any traffic happening
351 on a block device queue. For more information (and the userspace
352 support tools needed), fetch the blktrace tools from:
354 git://git.kernel.dk/blktrace.git
356 Tracing also is possible using the ftrace interface, e.g.:
358 echo 1 > /sys/block/sda/sda1/trace/enable
359 echo blk > /sys/kernel/debug/tracing/current_tracer
360 cat /sys/kernel/debug/tracing/trace_pipe
364 config DYNAMIC_FTRACE
365 bool "enable/disable ftrace tracepoints dynamically"
366 depends on FUNCTION_TRACER
367 depends on HAVE_DYNAMIC_FTRACE
370 This option will modify all the calls to ftrace dynamically
371 (will patch them out of the binary image and replaces them
372 with a No-Op instruction) as they are called. A table is
373 created to dynamically enable them again.
375 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise
376 has native performance as long as no tracing is active.
378 The changes to the code are done by a kernel thread that
379 wakes up once a second and checks to see if any ftrace calls
380 were made. If so, it runs stop_machine (stops all CPUS)
381 and modifies the code to jump over the call to ftrace.
383 config FUNCTION_PROFILER
384 bool "Kernel function profiler"
385 depends on FUNCTION_TRACER
388 This option enables the kernel function profiler. A file is created
389 in debugfs called function_profile_enabled which defaults to zero.
390 When a 1 is echoed into this file profiling begins, and when a
391 zero is entered, profiling stops. A file in the trace_stats
392 directory called functions, that show the list of functions that
393 have been hit and their counters.
397 config FTRACE_MCOUNT_RECORD
399 depends on DYNAMIC_FTRACE
400 depends on HAVE_FTRACE_MCOUNT_RECORD
402 config FTRACE_SELFTEST
405 config FTRACE_STARTUP_TEST
406 bool "Perform a startup test on ftrace"
408 select FTRACE_SELFTEST
410 This option performs a series of startup tests on ftrace. On bootup
411 a series of tests are made to verify that the tracer is
412 functioning properly. It will do tests on all the configured
416 bool "Memory mapped IO tracing"
417 depends on HAVE_MMIOTRACE_SUPPORT && PCI
420 Mmiotrace traces Memory Mapped I/O access and is meant for
421 debugging and reverse engineering. It is called from the ioremap
422 implementation and works via page faults. Tracing is disabled by
423 default and can be enabled at run-time.
425 See Documentation/trace/mmiotrace.txt.
426 If you are not helping to develop drivers, say N.
428 config MMIOTRACE_TEST
429 tristate "Test module for mmiotrace"
430 depends on MMIOTRACE && m
432 This is a dumb module for testing mmiotrace. It is very dangerous
433 as it will write garbage to IO memory starting at a given address.
434 However, it should be safe to use on e.g. unused portion of VRAM.
436 Say N, unless you absolutely know what you are doing.
440 endif # TRACING_SUPPORT