linux-kernel - Re: [PATCH] perf annotate: Remove hist__account

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20190314120434.GD4406@krava>
Date:   Thu, 14 Mar 2019 13:04:34 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Jin Yao <yao.jin@...ux.intel.com>
Cc:     acme@...nel.org, jolsa@...nel.org, peterz@...radead.org,
        mingo@...hat.com, alexander.shishkin@...ux.intel.com,
        Linux-kernel@...r.kernel.org, ak@...ux.intel.com,
        kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH] perf annotate: Remove hist__account_cycles from callback

On Wed, Mar 13, 2019 at 04:22:54AM +0800, Jin Yao wrote:
> The hist__account_cycles is executed when the hist_iter__branch_callback
> is called. But it looks it's not necessary. In hist__account_cycles, it
> already walks on all branch entries.
> 
> This patch moves the hist__account_cycles out of callback, now the data
> processing is much faster than before.
> 
> For example,
> perf record -b ...
> perf annotate
> 
> The before/after output should be no change.

so in the old code it was called multiple times per sample,
while after your change it's called just once per sample

it increases cycles stats for symbol, so it's strange
the behaviour is the same.. could you please exaplin this
in more detail?

> 
> Signed-off-by: Jin Yao <yao.jin@...ux.intel.com>
> ---
>  tools/perf/builtin-annotate.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
> index 67f9d9f..77deb3a 100644
> --- a/tools/perf/builtin-annotate.c
> +++ b/tools/perf/builtin-annotate.c
> @@ -159,8 +159,6 @@ static int hist_iter__branch_callback(struct hist_entry_iter *iter,
>  	struct perf_evsel *evsel = iter->evsel;
>  	int err;
>  
> -	hist__account_cycles(sample->branch_stack, al, sample, false);
> -

there's similar code in perf report, could you please cover
that as well?

thanks,
jirka

>  	bi = he->branch_info;
>  	err = addr_map_symbol__inc_samples(&bi->from, sample, evsel);
>  
> @@ -199,6 +197,8 @@ static int process_branch_callback(struct perf_evsel *evsel,
>  	if (a.map != NULL)
>  		a.map->dso->hit = 1;
>  
> +	hist__account_cycles(sample->branch_stack, al, sample, false);
> +
>  	ret = hist_entry_iter__add(&iter, &a, PERF_MAX_STACK_DEPTH, ann);
>  	return ret;
>  }
> -- 
> 2.7.4
>