Commit be87ab0a authored by Waiman Long's avatar Waiman Long Committed by Linus Torvalds

psi: clarify the units used in pressure files

The output of the PSI files show a bunch of numbers with no unit.  The
psi.txt documentation file also does not indicate what units are used.
One can only find out by looking at the source code.  The units are
percentage for the averages and useconds for the total.  Make the
information easier to find by documenting the units in psi.txt.

Link: http://lkml.kernel.org/r/20190402193810.3450-1-longman@redhat.comSigned-off-by: default avatarWaiman Long <longman@redhat.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent c6f3c5ee
...@@ -56,12 +56,12 @@ situation from a state where some tasks are stalled but the CPU is ...@@ -56,12 +56,12 @@ situation from a state where some tasks are stalled but the CPU is
still doing productive work. As such, time spent in this subset of the still doing productive work. As such, time spent in this subset of the
stall state is tracked separately and exported in the "full" averages. stall state is tracked separately and exported in the "full" averages.
The ratios are tracked as recent trends over ten, sixty, and three The ratios (in %) are tracked as recent trends over ten, sixty, and
hundred second windows, which gives insight into short term events as three hundred second windows, which gives insight into short term events
well as medium and long term trends. The total absolute stall time is as well as medium and long term trends. The total absolute stall time
tracked and exported as well, to allow detection of latency spikes (in us) is tracked and exported as well, to allow detection of latency
which wouldn't necessarily make a dent in the time averages, or to spikes which wouldn't necessarily make a dent in the time averages,
average trends over custom time frames. or to average trends over custom time frames.
Cgroup2 interface Cgroup2 interface
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