From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1754556AbbHYGTs (ORCPT <rfc822;w@1wt.eu>);
	Tue, 25 Aug 2015 02:19:48 -0400
Received: from mail-pd0-f181.google.com ([209.85.192.181]:34774 "EHLO
	mail-pd0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750768AbbHYGTq (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 25 Aug 2015 02:19:46 -0400
Message-ID: <55DC0900.3010500@gmail.com>
Date: Mon, 24 Aug 2015 23:19:44 -0700
From: David Ahern <dsahern@gmail.com>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.10; rv:31.0) Gecko/20100101 Thunderbird/31.7.0
MIME-Version: 1.0
To: Namhyung Kim <namhyung@kernel.org>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
CC: Ingo Molnar <mingo@kernel.org>, Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Jiri Olsa <jolsa@redhat.com>, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC/PATCH] perf sched: Implement 'perf sched runtime' command
References: <1440483083-19376-1-git-send-email-namhyung@kernel.org>
In-Reply-To: <1440483083-19376-1-git-send-email-namhyung@kernel.org>
Content-Type: text/plain; charset=windows-1252; format=flowed
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 8/24/15 11:11 PM, Namhyung Kim wrote:
>
> +static int perf_sched__read_runtime_events(struct perf_sched *sched)
> +{
> +	const struct perf_evsel_str_handler handlers[] = {
> +		{ "sched:sched_switch",	      process_sched_switch_event, },
> +		{ "sched:sched_stat_runtime", process_sched_runtime_event, },
> +		{ "sched:sched_stat_sleep",   process_sched_sleep_event, },
> +		{ "sched:sched_stat_wait",    process_sched_wait_event, },
> +		{ "sched:sched_stat_iowait",  process_sched_iowait_event, },
> +		{ "sched:sched_migrate_task", process_sched_migrate_task_event, },
> +	};

I like the concept (obviously since I have invested so much time in 
other solutions). But... you cannot rely on the sched_stat tracepoints 
being enabled. I believe it is a performance hit to have 
CONFIG_SCHEDSTATS enabled and distributions (e.g., Fedora) do not have 
it enabled.