From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4505 invoked by alias); 29 Oct 2013 14:05:47 -0000 Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org Received: (qmail 4496 invoked by uid 89); 29 Oct 2013 14:05:46 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-2.6 required=5.0 tests=BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.2 X-HELO: out4-smtp.messagingengine.com Received: from out4-smtp.messagingengine.com (HELO out4-smtp.messagingengine.com) (66.111.4.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-SHA encrypted) ESMTPS; Tue, 29 Oct 2013 14:05:45 +0000 Received: from compute2.internal (compute2.nyi.mail.srv.osa [10.202.2.42]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id 8BB6920DFE; Tue, 29 Oct 2013 10:05:41 -0400 (EDT) Received: from frontend1 ([10.202.2.160]) by compute2.internal (MEProxy); Tue, 29 Oct 2013 10:05:41 -0400 Received: from localhost.localdomain (unknown [82.181.7.205]) by mail.messagingengine.com (Postfix) with ESMTPA id A9EB7C00E84; Tue, 29 Oct 2013 10:05:39 -0400 (EDT) Message-ID: <526FC0B2.6060206@iki.fi> Date: Tue, 29 Oct 2013 14:05:00 -0000 From: Pekka Enberg User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.0 MIME-Version: 1.0 To: Hemant Kumar CC: David Ahern , Srikar Dronamraju , LKML , Peter Zijlstra , Oleg Nesterov , "hegdevasant@linux.vnet.ibm.com" , Ingo Molnar , "anton@redhat.com" , "systemtap@sourceware.org" , Namhyung Kim , Masami Hiramatsu , "aravinda@linux.vnet.ibm.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> <526F862E.9060203@linux.vnet.ibm.com> In-Reply-To: <526F862E.9060203@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2013-q4/txt/msg00128.txt.bz2 On 10/29/2013 11:55 AM, Hemant Kumar wrote: > 1. Where this cache should be? Keeping it in tracing directory inside > the debugfs > directory should seem more feasible. And, shall this cache be shareable? You can't share all of the cache because otherwise you'll expose details on binaries that not everyone has access to. It might make sense to split the cache into two parts: system markers and user markers and share the former. > 2. perf record is a performance intensive process, can we allow the > delay due to > this searching process here? I think scanning is OK if the user specified a SDT markers but not otherwise. Perhaps you can use a bloom filter to quickly check if the user passed a SDT marker or not. Pekka