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| author |   Andi Kleen <ak@linux.intel.com> | 2014-02-28 06:02:14 -0800 |
|---|---|---|
| committer |   Arnaldo Carvalho de Melo <acme@redhat.com> | 2014-03-14 11:20:44 -0300 |
| commit | b63940970492f5f187d546e191bc2c6831491fe3 (patch) | |
| tree | 7cb6844706b7bcb238ccbad8fb311a27803836c8 /tools/perf/Documentation | |
| parent | perf bench: Add futex-requeue microbenchmark (diff) | |
| download | linux-dev-b63940970492f5f187d546e191bc2c6831491fe3.tar.xz linux-dev-b63940970492f5f187d546e191bc2c6831491fe3.zip | |
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 <ak@linux.intel.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1393596135-4227-2-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/Documentation')
| -rw-r--r-- | tools/perf/Documentation/perf-mem.txt | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/tools/perf/Documentation/perf-mem.txt b/tools/perf/Documentation/perf-mem.txt index 888d51137fbe..1d78a4064da4 100644 --- a/tools/perf/Documentation/perf-mem.txt +++ b/tools/perf/Documentation/perf-mem.txt @@ -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>...:: |