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authorSrivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>2019-10-10 11:51:01 -0700
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2019-10-12 20:49:33 -0400
commitfc64e4ad80d4b72efce116f87b3174f0b7196f8e (patch)
treef4c1f3db8217dd7afa8b988c19684535b1d04068
parent98dc19c11470ee6048aba723d77079ad2cda8a52 (diff)
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tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
max_latency is intended to record the maximum ever observed hardware latency, which may occur in either part of the loop (inner/outer). So we need to also consider the outer-loop sample when updating max_latency. Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu Fixes: e7c15cd8a113 ("tracing: Added hardware latency tracer") 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>
-rw-r--r--kernel/trace/trace_hwlat.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index a0251a78807d..862f4b0139fc 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -256,6 +256,8 @@ static int get_sample(void)
/* Keep a running maximum ever recorded hardware latency */
if (sample > tr->max_latency)
tr->max_latency = sample;
+ if (outer_sample > tr->max_latency)
+ tr->max_latency = outer_sample;
}
out: