Lines Matching +full:wakeup +full:- +full:latency +full:- +full:us
1 # SPDX-License-Identifier: GPL-2.0-only
21 API, which will be used by other function-entry hooking
27 See Documentation/trace/ftrace-design.rst
32 See Documentation/trace/ftrace-design.rst
45 See Documentation/trace/ftrace-design.rst
80 See Documentation/trace/ftrace-design.rst
85 See Documentation/trace/ftrace-design.rst
90 Arch supports the gcc options -pg with -mfentry
95 Arch supports the gcc options -pg with -mrecord-mcount and -nop-mcount
100 Arch supports objtool --mcount
105 Arch supports the objtool options --mcount with --mnop.
184 # Minimum requirements an architecture has to meet for us to
203 bool "Boot-time Tracing support"
222 by using a compiler feature to insert a small, 5-byte No-Operation
227 small and not measurable even in micro-benchmarks (at least on
253 enable it via the trace option funcgraph-retval.
264 enable it via the trace option funcgraph-retaddr.
274 replace them with a No-Op instruction) on boot up. During
348 stack-trace saved. If this is configured with DYNAMIC_FTRACE
367 bool "Interrupts-off Latency Tracer"
377 This option measures the time spent in irqs-off critical
381 disabled by default and can be runtime (re-)started
387 enabled. This option and the preempt-off timing option can be
391 bool "Preemption-off Latency Tracer"
401 This option measures the time spent in preemption-off critical
405 disabled by default and can be runtime (re-)started
411 enabled. This option and the irqs-off timing option can be
415 bool "Scheduling Latency Tracer"
421 This tracer tracks the latency of the highest priority task
440 hwlat_detector/width - time in usecs for how long to spin for
441 hwlat_detector/window - time in usecs between the start of each
446 for "window - width" microseconds, where the system can
457 file. Every time a latency is greater than tracing_thresh, it will
465 In the context of high-performance computing (HPC), the Operating
469 can cause noise to the system. Moreover, hardware-related jobs can
476 increasing a per-cpu interference counter. It saves an interference
481 hardware noise counter increases, pointing to a hardware-related
501 to find sources of wakeup latencies of real-time threads.
503 The tracer creates a per-cpu kernel thread with real-time priority.
504 The tracer thread sets a periodic timer to wakeup itself, and goes
505 to sleep waiting for the timer to fire. At the wakeup, the thread
506 then computes a wakeup latency value as the difference between
511 timer latency observed at the hardirq context before the
512 activation of the thread. The second is the timer latency observed
531 default and can be enabled at run-time.
581 or irq latency tracers are enabled, as those need to swap as well
598 The "all branch" profiler will profile every if-statement in the
691 bool "Enable fprobe-based dynamic events"
717 bool "Enable kprobes-based dynamic events"
730 This option is also required by perf-probe subcommand of perf tools.
743 functions are protected from kprobe-events to prevent an infinite
754 bool "Enable uprobes-based dynamic events"
768 This option is required if you plan to use perf-probe subcommand
806 depends on $(cc-option,-mrecord-mcount)
829 tracing_map is a special-purpose lock-free map for tracing,
830 separated out as a stand-alone facility in order to allow it
841 Synthetic events are user-defined trace events that can be
845 by way of an in-kernel API.
857 User trace events are user-defined trace events that
883 Inter-event tracing of quantities such as latencies is also
893 Allow user-space to inject a specific trace event into the ring
1068 TBD - enable a way to actually call the syscalls as we test their
1079 is not done correctly, it will cause non-deterministic failures.
1139 tristate "Test module to create a preempt / IRQ disable delay thread to test latency tracers"
1142 Select this option to build a test module that can help test latency
1148 irq-disabled critical sections for 500us:
1151 What's more, if you want to attach the test on the cpu which the latency
1158 tristate "Test module for in-kernel synthetic event generation"
1162 functionality of in-kernel synthetic event definition and
1171 tristate "Test module for in-kernel kprobe event generation"
1175 functionality of in-kernel kprobe event definition.
1192 - Helps developers verify that nothing is broken.
1194 - Provides educational information to support the details
1196 Documentation/trace/histogram-design.rst.