perf tools: Add a 'percore' event qualifier

Add a 'percore' event qualifier, like cpu/event=0,umask=0x3,percore=1/,
that sums up the event counts for both hardware threads in a core.

We can already do this with --per-core, but it's often useful to do
this together with other metrics that are collected per hardware thread.
So we need to support this per-core counting on a event level.

This can be implemented in only the user tool, no kernel support needed.

 v4:
 ---
 1. Add Arnaldo's patch which updates the documentation for
    this new qualifier.
 2. Rebase to latest perf/core branch

 v3:
 ---
 Simplify the code according to Jiri's comments.
 Before:
   "return term->val.percore ? true : false;"
 Now:
   "return term->val.percore;"

 v2:
 ---
 Change the qualifier name from 'coresum' to 'percore' according to
 comments from Jiri and Andi.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jin Yao <yao.jin@intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1555077590-27664-2-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt
index 138fb6e94b3c..18ed1b0fceb3 100644
--- a/tools/perf/Documentation/perf-list.txt
+++ b/tools/perf/Documentation/perf-list.txt
@@ -199,6 +199,18 @@ also be supplied. For example:
 
   perf stat -C 0 -e 'hv_gpci/dtbp_ptitc,phys_processor_idx=0x2/' ...
 
+EVENT QUALIFIERS:
+
+It is also possible to add extra qualifiers to an event:
+
+percore:
+
+Sums up the event counts for all hardware threads in a core, e.g.:
+
+
+  perf stat -e cpu/event=0,umask=0x3,percore=1/
+
+
 EVENT GROUPS
 ------------