Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752496Ab3J2Tlf (ORCPT ); Tue, 29 Oct 2013 15:41:35 -0400 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:49205 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751345Ab3J2Tle (ORCPT ); Tue, 29 Oct 2013 15:41:34 -0400 Message-ID: <52700F66.8080105@linux.vnet.ibm.com> Date: Wed, 30 Oct 2013 01:11:26 +0530 From: Hemant Kumar User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7 MIME-Version: 1.0 To: Pekka Enberg 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> <526FC0B2.6060206@iki.fi> In-Reply-To: <526FC0B2.6060206@iki.fi> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13102919-9574-0000-0000-00000A57124A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1326 Lines: 42 On 10/29/2013 07:35 PM, Pekka Enberg wrote: > 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. Correct, that was one of the reason to be worried. And since, to a normal user debugfs is not allowed to be entered, then we can keep that inside debugfs/tracing subdirectory. > > It might make sense to split the cache into two parts: system markers > and user markers and share the former. > Ok... >> 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. > True, bloom filters may help in this case with a quick check. -- Thanks Hemant Kumar -- 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/