diff options
| author | Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu> | 2019-10-10 11:51:01 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-17 13:43:58 -0700 |
| commit | 49495fb2d7f586b1a5e759973f85ed7a7e2ec07b (patch) | |
| tree | b8eac724864988f1d3033058c3ed5feba3dfd0b5 /kernel | |
| parent | 2d058b19b10975054516da34ce225b32598b51e0 (diff) | |
tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
commit fc64e4ad80d4b72efce116f87b3174f0b7196f8e upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/trace_hwlat.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c index b42886167d56..bff6c033d70e 100644 --- a/kernel/trace/trace_hwlat.c +++ b/kernel/trace/trace_hwlat.c @@ -258,6 +258,8 @@ 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: |