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tracing/hwlat: Report total time spent in all NMIs during the sample

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nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.

Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu

Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
This commit is contained in:
Srivatsa S. Bhat (VMware) 2019-10-10 11:50:46 -07:00 committed by Steven Rostedt (VMware)
parent 7f8557b88d
commit 98dc19c114
1 changed files with 1 additions and 1 deletions
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2
kernel/trace/trace_hwlat.c
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@ -150,7 +150,7 @@ void trace_hwlat_callback(bool enter)
if (enter)
nmi_ts_start = time_get();
else
nmi_total_ts = time_get() - nmi_ts_start;
nmi_total_ts += time_get() - nmi_ts_start;
}
if (enter)