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

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commit 98dc19c114 upstream.

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: 7b2c862501 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Srivatsa S. Bhat (VMware)
2019-10-10 11:50:46 -07:00
committed by Greg Kroah-Hartman
parent 30ec4150a4
commit 2d058b19b1
1 changed files with 1 additions and 1 deletions
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2
kernel/trace/trace_hwlat.c
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@ -152,7 +152,7 @@ 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)