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Diffstat (limited to 'Documentation/trace/hwlat_detector.rst')
-rw-r--r-- | Documentation/trace/hwlat_detector.rst | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/Documentation/trace/hwlat_detector.rst b/Documentation/trace/hwlat_detector.rst index 5739349649c8..de94b499b0bc 100644 --- a/Documentation/trace/hwlat_detector.rst +++ b/Documentation/trace/hwlat_detector.rst @@ -76,8 +76,13 @@ in /sys/kernel/tracing: - tracing_cpumask - the CPUs to move the hwlat thread across - hwlat_detector/width - specified amount of time to spin within window (usecs) - hwlat_detector/window - amount of time between (width) runs (usecs) + - hwlat_detector/mode - the thread mode -The hwlat detector's kernel thread will migrate across each CPU specified in -tracing_cpumask between each window. To limit the migration, either modify -tracing_cpumask, or modify the hwlat kernel thread (named [hwlatd]) CPU -affinity directly, and the migration will stop. +By default, one hwlat detector's kernel thread will migrate across each CPU +specified in cpumask at the beginning of a new window, in a round-robin +fashion. This behavior can be changed by changing the thread mode, +the available options are: + + - none: do not force migration + - round-robin: migrate across each CPU specified in cpumask [default] + - per-cpu: create one thread for each cpu in tracing_cpumask |