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| author |   Viktor Rosendahl (BMW) <viktor.rosendahl@gmail.com> | 2019-10-09 00:08:22 +0200 |
|---|---|---|
| committer |   Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-11-13 09:37:28 -0500 |
| commit | 793937236d1ee032d2ee5ccc27bdd280a04e766e (patch) | |
| tree | e3662d9c0f5dbfc0fc8663af5a33622ff9dda763 /kernel/trace/Kconfig | |
| parent | ftrace: Implement fs notification for tracing_max_latency (diff) | |
| download | linux-dev-793937236d1ee032d2ee5ccc27bdd280a04e766e.tar.xz linux-dev-793937236d1ee032d2ee5ccc27bdd280a04e766e.zip | |
preemptirq_delay_test: Add the burst feature and a sysfs trigger
This burst feature enables the user to generate a burst of
preempt/irqsoff latencies. This makes it possible to test whether we
are able to detect latencies that systematically occur very close to
each other.
The maximum burst size is 10. We also create 10 identical test
functions, so that we get 10 different backtraces; this is useful
when we want to test whether we can detect all the latencies in a
burst. Otherwise, there would be no easy way of differentiating
between which latency in a burst was captured by the tracer.
In addition, there is a sysfs trigger, so that it's not necessary to
reload the module to repeat the test. The trigger will appear as
/sys/kernel/preemptirq_delay_test/trigger in sysfs.
Link: http://lkml.kernel.org/r/20191008220824.7911-3-viktor.rosendahl@gmail.com
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Viktor Rosendahl (BMW) <viktor.rosendahl@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 624a05e99b0b..d25314bc7a1c 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -760,9 +760,9 @@ config PREEMPTIRQ_DELAY_TEST configurable delay. The module busy waits for the duration of the critical section. - For example, the following invocation forces a one-time irq-disabled - critical section for 500us: - modprobe preemptirq_delay_test test_mode=irq delay=500000 + For example, the following invocation generates a burst of three + irq-disabled critical sections for 500us: + modprobe preemptirq_delay_test test_mode=irq delay=500 burst_size=3 If unsure, say N |