Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932198AbZLOOPn (ORCPT ); Tue, 15 Dec 2009 09:15:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760304AbZLOOPl (ORCPT ); Tue, 15 Dec 2009 09:15:41 -0500 Received: from mail-bw0-f227.google.com ([209.85.218.227]:52474 "EHLO mail-bw0-f227.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754027AbZLOOPk (ORCPT ); Tue, 15 Dec 2009 09:15:40 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=uCRl80zbf7UnfgUuKpmlq/Pwy5ZLhMxuVXO0qrYSYITZjHYhsKG01gJzx11+GNeH4F Z3ZfCVjmoIzSP1KrQt0S7hJ6MJo34yvLuGQpD9PRd5DAQhjnoqJ9NjV7ImtXXkau2sre /jYxEqYf82bR25Xmp1YXYnliqvlEj/19fDoA8= Date: Tue, 15 Dec 2009 15:15:35 +0100 From: Frederic Weisbecker To: Xiao Guangrong Cc: Ingo Molnar , Thomas Gleixner , Peter Zijlstra , Steven Rostedt , LKML Subject: Re: [PATCH 0/4] perf_event: introduce 'perf timer' to analyze timer's behavior Message-ID: <20091215141533.GB5833@nowhere> References: <4B27702F.1080507@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4B27702F.1080507@cn.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1778 Lines: 37 On Tue, Dec 15, 2009 at 07:17:03PM +0800, Xiao Guangrong wrote: > Hi, > > We introduce 'perf timer' in this patchset, it can analyze timer > latency and timer function handle time, the usage and result is > like below: > > # perf timer record > # perf timer lat --print-lat --print-handle > ------------------------------------------------------------------------------------------------------- > | Timer | TYPE | Avg-latency | Max-latency | Max-latency-at-TS |Max-lat-at-Task | > |0xf7ad1f5c |hrtimer |996068.500 ns|1607650 ns|10270128658526 |init | > |0xf7903f04 |timer |0.625 HZ|2 HZ|10270344082394 |swapper | > |0xf787a05c |hrtimer |200239.500 ns|359929 ns|10269316024808 |main | > |main :[ PROF]|itimer |0.000 HZ|0 HZ|10237021270557 |main | > |main :[VIRTUAL]|itimer |0.000 HZ|0 HZ|10257314773501 |main | Cool! This is really a good work and a good idea. Just have some neats in mind. hrtimers and timers don't have the same latency and granularity requirements. As you show it, timers have an HZ granularity and hrtimers are about nanoseconds, and mixing them up in the same array of latency report is too messy. They don't have the same granularity/latency scope so they should be reported separately. Otherwise it's like mixing slothes and flies latency results after a fly swat attack test ;-) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/