[tip:perf/core] perf report: Documentation average IPC and IPC coverage

From: tip-bot for Jin Yao
Date: Tue Dec 18 2018 - 09:01:06 EST

Commit-ID: 239ca3e78609378a1ed5d9db1c7db629a71c2857
Gitweb: https://git.kernel.org/tip/239ca3e78609378a1ed5d9db1c7db629a71c2857
Author: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 30 Nov 2018 21:54:57 +0800
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Mon, 17 Dec 2018 14:55:49 -0300

perf report: Documentation average IPC and IPC coverage

Add explanations for new columns "IPC" and "IPC coverage" in perf

Update the description according to Ingo's comments.

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
Reviewed-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1543586097-27632-5-git-send-email-yao.jin@xxxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/Documentation/perf-report.txt | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/tools/perf/Documentation/perf-report.txt b/tools/perf/Documentation/perf-report.txt
index 474a4941f65d..ed2bf37ab132 100644
--- a/tools/perf/Documentation/perf-report.txt
+++ b/tools/perf/Documentation/perf-report.txt
@@ -126,6 +126,14 @@ OPTIONS
And default sort keys are changed to comm, dso_from, symbol_from, dso_to
and symbol_to, see '--branch-stack'.

+ When the sort key symbol is specified, columns "IPC" and "IPC Coverage"
+ are enabled automatically. Column "IPC" reports the average IPC per function
+ and column "IPC coverage" reports the percentage of instructions with
+ sampled IPC in this function. IPC means Instruction Per Cycle. If it's low,
+ it indicates there may be a performance bottleneck when the function is
+ executed, such as a memory access bottleneck. If a function has high overhead
+ and low IPC, it's worth further analyzing it to optimize its performance.
If the --mem-mode option is used, the following sort keys are also available
(incompatible with --branch-stack):
symbol_daddr, dso_daddr, locked, tlb, mem, snoop, dcacheline.