Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753621Ab3J3KWo (ORCPT ); Wed, 30 Oct 2013 06:22:44 -0400 Received: from mail4.hitachi.co.jp ([133.145.228.5]:44090 "EHLO mail4.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751838Ab3J3KWm (ORCPT ); Wed, 30 Oct 2013 06:22:42 -0400 Message-ID: <5270DDEE.8070606@hitachi.com> Date: Wed, 30 Oct 2013 19:22:38 +0900 From: Masami Hiramatsu Organization: Hitachi, Ltd., Japan User-Agent: Mozilla/5.0 (Windows NT 5.2; rv:13.0) Gecko/20120614 Thunderbird/13.0.1 MIME-Version: 1.0 To: Pekka Enberg Cc: David Ahern , Srikar Dronamraju , Hemant Kumar , LKML , Peter Zijlstra , Oleg Nesterov , "hegdevasant@linux.vnet.ibm.com" , Ingo Molnar , "anton@redhat.com" , "systemtap@sourceware.org" , Namhyung Kim , "aravinda@linux.vnet.ibm.com" , "yrl.pp-manager.tt@hitachi.com" Subject: Re: [PATCH v4 2/3] Support for perf to probe into SDT markers: References: <20131023044511.1886.82571.stgit@hemant-fedora> <20131023050502.1886.15779.stgit@hemant-fedora> <20131025125921.GA29424@linux.vnet.ibm.com> <526A8C2B.7000401@gmail.com> <526E24EA.2040701@iki.fi> <526E9808.4030607@gmail.com> <526EB0C3.2080304@iki.fi> In-Reply-To: <526EB0C3.2080304@iki.fi> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1566 Lines: 41 (2013/10/29 3:45), Pekka Enberg wrote: > On 10/28/13 6:59 PM, David Ahern wrote: > > I often use perf-list to lookup an exact event name, and I do not want > > to see it taking many seconds to minutes to run (not everyone is > > running on an SSD). I also run perf on many different OS versions with > > an NFS home directory, and do not want to see a cache explosion (I > > have buildid disabled for this reason). > > I am talking about reasonable defaults - the 'default' part implies that > people can change the behavior. So we absolutely should also have > something like this for power users such as yourself: > > perf config sdt.scan false Ah, I like this perf-config to store the default/customized values ;) > That said, the 'reasonable' part suggests that 'perf list' must not take > seconds or minutes (!) for every run. I'd start with implementing a > naive scan and seeing where it takes us. It's not like it's rocket > science to ignore network mounts or revert to a whitelist of paths if > necessary. I think it is reasonable to scan only $PATH and ld.so.cache (the result of ldconfig --print-cache) by default. :) Thank you, -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com -- 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/