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Subject[PATCH 1/2] perf, tools, mem: Clarify load-latency in documentation
From: Andi Kleen <>

Clarify in the documentation that perf mem report reports
use-latency, not load/store-latency on Intel systems.
This often causes confusion with users.

Signed-off-by: Andi Kleen <>
tools/perf/Documentation/perf-mem.txt | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt
index 888d511..1d78a40 100644
--- a/tools/perf/Documentation/perf-mem.txt
+++ b/tools/perf/Documentation/perf-mem.txt
@@ -18,6 +18,10 @@ from it, into Perf record options are accepted and are passed through
"perf mem -t <TYPE> report" displays the result. It invokes perf report with the
right set of options to display a memory access profile.

+Note that on Intel systems the memory latency reported is the use-latency,
+not the pure load (or store latency). Use latency includes any pipeline
+queueing delays in addition to the memory subsystem latency.

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