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Subject[tip:perf/urgent] perf top: Display the LBR stats in callchain entry
Commit-ID:  590ac60d8aa929bd21e35cd95a7d8720d00eb4f3
Gitweb: https://git.kernel.org/tip/590ac60d8aa929bd21e35cd95a7d8720d00eb4f3
Author: Jin Yao <yao.jin@linux.intel.com>
AuthorDate: Wed, 31 Oct 2018 19:06:35 +0800
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 5 Nov 2018 14:37:11 -0300

perf top: Display the LBR stats in callchain entry

'perf report' has supported the displaying of LBR stats (such as cycles,
predicted%) in callchain entry.

For example:

$ perf report --branch-history --stdio

--1.01%--intel_idle mwait.h:29
intel_idle cpufeature.h:164 (cycles:5)
intel_idle cpufeature.h:164 (predicted:76.4%)
intel_idle mwait.h:102 (cycles:41)
intel_idle current.h:15

While 'perf top' doesn't support that.

For example:

$ perf top -a -b --call-graph branch

- 13.86% 0.23% [kernel] [k] __x86_indirect_thunk_rax
- 13.65% __x86_indirect_thunk_rax
+ 1.69% do_syscall_64
+ 1.68% do_select
+ 1.41% ktime_get
+ 0.70% __schedule
+ 0.62% do_sys_poll
0.58% __x86_indirect_thunk_rax

Actually it's very easy to enable this feature in 'perf top'.

With this patch, the result is:

$ perf top -a -b --call-graph branch

$ - 13.58% 0.00% [kernel] [k] __x86_indirect_thunk_rax
$ - 13.57% __x86_indirect_thunk_rax (predicted:93.9%)
$ + 1.78% do_select (cycles:2)
$ + 1.68% perf_pmu_disable.part.99 (cycles:1)
$ + 1.45% ___sys_recvmsg (cycles:25)
$ + 0.81% unix_stream_sendmsg (cycles:18)
$ + 0.80% ktime_get (cycles:400)
$ 0.58% pick_next_task_fair (cycles:47)
$ + 0.56% i915_request_retire (cycles:2)
$ + 0.52% do_sys_poll (cycles:4)

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1540983995-20462-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/builtin-top.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index b2838de13de0..aa0c73e57924 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1429,6 +1429,9 @@ int cmd_top(int argc, const char **argv)
}
}

+ if (opts->branch_stack && callchain_param.enabled)
+ symbol_conf.show_branchflag_count = true;
+
sort__mode = SORT_MODE__TOP;
/* display thread wants entries to be collapsed in a different tree */
perf_hpp_list.need_collapse = 1;
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