perf mem: Clarify load-latency in documentation

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 <[email protected]>
Cc: Stephane Eranian <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
This commit is contained in:
Andi Kleen 2014-02-28 06:02:14 -08:00 • committed by Arnaldo Carvalho de Melo
commit b639409704

View file

@ -18,6 +18,10 @@ from it, into perf.data. 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.
OPTIONS
-------
<command>...::