Lines Matching refs:a
87 Adds a very slight overhead to tracing when enabled.
172 by using a compiler feature to insert a small, 5-byte No-Operation
174 sequence is then dynamically patched into a tracer call when
186 Enable the kernel to trace a function at both its return
189 draw a call graph for each thread with some information like
191 address on the current task structure into a stack of calls.
201 replace them with a No-Op instruction) on boot up. During
202 compile time, a table is made of all the locations that ftrace
213 This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but
233 When a 1 is echoed into this file profiling begins, and when a
251 kernel executes, and keeping a maximum stack depth value and
285 The default measurement method is a maximum search, which is
310 The default measurement method is a maximum search, which is
336 spinning in a loop looking for interruptions caused by
337 something other than the kernel. For example, if a
338 System Management Interrupt (SMI) takes a noticeable amount of
340 if a system is reliable for Real Time tasks.
358 periodically non responsive. Do not run this tracer on a
362 file. Every time a latency is greater than tracing_thresh, it will
396 bool "Create a snapshot trace buffer"
410 Allow doing a snapshot of a single CPU buffer instead of a
419 When this is enabled, this adds a little more overhead to the
424 and already adds the overhead (plus a lot more).
434 The branch profiling is a software profiler. It will add hooks
435 into the C conditionals to test which path a branch takes.
438 are annotated with a likely or unlikely macro.
444 Either of the above profilers adds a bit of overhead to the system.
450 No branch profiling. Branch profiling adds a bit of overhead.
463 Note: this will add a significant overhead; only turn this
478 This configuration, when enabled, will impose a great overhead
498 "Trace likely/unlikely profiler" is that this is not a
500 events into a running trace buffer to see when and where the
516 on a given queue. Tracing allows you to see any traffic happening
517 on a block device queue. For more information (and the userspace
560 recursion or any unexpected execution path which leads to a kernel
603 bool "Enable BPF programs to override a kprobed function"
608 Allows BPF to override the execution of a probed function and
609 set a different return value. This is used for error injection.
644 tracing_map is a special-purpose lock-free map for tracing,
645 separated out as a stand-alone facility in order to allow it
678 reading a debugfs/tracefs file. They're useful for
693 Allow user-space to inject a specific trace event into the ring
702 When the tracepoint is enabled, it kicks off a kernel thread that
708 The string written to the tracepoint is a static string of 128 bytes
709 to keep the time the same. The initial string is simply a write of
713 As it is a tight loop, it benchmarks as hot cache. That's fine because
732 This option creates a test to stress the ring buffer and benchmark it.
735 a producer and consumer that will run for 10 seconds and sleep for
737 it recorded and give a rough estimate of how long each iteration took.
753 To fix this, there's a special macro in the kernel that can be used
781 Note that on a kernel compiled with this config, ftrace will
788 bool "Perform a startup test on ftrace"
792 This option performs a series of startup tests on ftrace. On bootup
793 a series of tests are made to verify that the tracer is
802 This option performs a test on all trace events in the system.
805 This may take some time run as there are a lot of events.
813 with the event enabled. This adds a bit more time for kernel boot
816 TBD - enable a way to actually call the syscalls as we test their
823 Run a simple self test on the ring buffer on boot up. Late in the
825 a thread per cpu. Each thread will write various size events
829 If any anomalies are discovered, a warning will be displayed
846 This is a dumb module for testing mmiotrace. It is very dangerous
847 as it will write garbage to IO memory starting at a given address.
853 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
856 Select this option to build a test module that can help test latency
857 tracers by executing a preempt or irq disable section with a user
861 For example, the following invocation generates a burst of three
871 This option creates a test module to check the base
884 This option creates a test module to check the base
897 dump out a bunch of internal details about the hist triggers
900 The hist_debug file serves a couple of purposes: