Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752088Ab2E2NCq (ORCPT ); Tue, 29 May 2012 09:02:46 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:33841 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751369Ab2E2NCp (ORCPT ); Tue, 29 May 2012 09:02:45 -0400 Message-ID: <4FC4C943.2030007@gmail.com> Date: Tue, 29 May 2012 21:04:03 +0800 From: Liu Zhiyou User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.24) Gecko/20111104 Red Hat/3.1.16-2.el6_1 Thunderbird/3.1.16 MIME-Version: 1.0 To: Xin Tong CC: Andi Kleen , linux-kernel Subject: Re: native_save_fl taking good amount of time in profile References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1744 Lines: 52 于 2012年05月26日 07:10, Xin Tong 写道: > i do not know its callers from the profile. one thing i am suspicious > of is that my kernel debug-info is wrong. by the way, what does the > function do ? > > Thanks > > Xin > > > On Fri, May 25, 2012 at 6:27 PM, Andi Kleen wrote: >> Xin Tong writes: >> >>> I have collected a profile on the whole system. But the only thing >>> that is really running is a mysql database server. I have noticed that >>> there is a function in kernel that took 5% of the overall running >>> time. what does native_save_fl do ? does it make sense that >>> native_save_fl takes the most amount of time among all kernel >>> functions ? >> What are the callers (-g)? It does not make sense normally. >> -Andi Xin Tong, Use perf record -g, then it will give you a call-graph. $ man perf-record -g, --call-graph Do call-graph (stack chain/backtrace) recording. $ man pref-report -g [type,min[,limit],order], --call-graph Display call chains using type, min percent threshold, optional print limit and order. type can be either: · flat: single column, linear exposure of call chains. · graph: use a graph tree, displaying absolute overhead rates. · fractal: like graph, but displays relative rates. Each branch of the tree is considered as a new profiled object. order can be either: - callee: callee based call graph. - caller: inverted caller based call graph. Default: fractal,0.5,callee. Regards, LIU Zhiyou -- 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/