linux-kernel - Re: [PATCH] perf top: Display the LBR stats in callchain entry

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Date:   Mon, 5 Nov 2018 08:31:59 +0800
From:   "Jin, Yao" <yao.jin@...ux.intel.com>
To:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com
Cc:     Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf top: Display the LBR stats in callchain entry

Hi,

Any comments for this patch?

Thanks
Jin Yao

On 10/31/2018 7:06 PM, Jin Yao wrote:
> 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 has not supported 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@...ux.intel.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 d21d875..7691b21 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1420,6 +1420,9 @@ 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;
>