From: Ian Rogers <irogers@google.com>
Date: Fri, 9 Feb 2024 20:49:47 +0000 (-0800)
Subject: perf metric: Don't remove scale from counts
X-Git-Tag: v6.9-rc1~108^2~88
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6d6be5eb45b423a37d746d3ee0fd0c78f76ead9f;p=thirdparty%2Fkernel%2Flinux.git

perf metric: Don't remove scale from counts

Counts were switched from the scaled saved value form to the
aggregated count to avoid double accounting. When this happened the
removing of scaling for a count should have been removed, however, it
wasn't and this wasn't observed as it normally doesn't matter because
a counter's scale is 1. A problem was observed with RAPL events that
are scaled.

Fixes: 37cc8ad77cf8 ("perf metric: Directly use counts rather than saved_value")
Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: James Clark <james.clark@arm.com>
Cc: Kaige Ye <ye@kaige.org>
Cc: John Garry <john.g.garry@oracle.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240209204947.3873294-5-irogers@google.com
---

diff --git a/tools/perf/util/stat-shadow.c b/tools/perf/util/stat-shadow.c
index e31426167852a..cf573ff3fa84f 100644
--- a/tools/perf/util/stat-shadow.c
+++ b/tools/perf/util/stat-shadow.c
@@ -414,12 +414,7 @@ static int prepare_metric(struct evsel **metric_events,
 				val = NAN;
 				source_count = 0;
 			} else {
-				/*
-				 * If an event was scaled during stat gathering,
-				 * reverse the scale before computing the
-				 * metric.
-				 */
-				val = aggr->counts.val * (1.0 / metric_events[i]->scale);
+				val = aggr->counts.val;
 				source_count = evsel__source_count(metric_events[i]);
 			}
 		}