Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751947AbZL3Lat (ORCPT ); Wed, 30 Dec 2009 06:30:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751659AbZL3Las (ORCPT ); Wed, 30 Dec 2009 06:30:48 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:44580 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751605AbZL3Lar (ORCPT ); Wed, 30 Dec 2009 06:30:47 -0500 Date: Wed, 30 Dec 2009 12:30:31 +0100 From: Ingo Molnar To: Peter Zijlstra Cc: Xiao Guangrong , Frederic Weisbecker , Thomas Gleixner , Steven Rostedt , Paul Mackerras , LKML Subject: Re: [PATCH v3 1/5] perf_event: introduce 'inject' event and get HZ Message-ID: <20091230113031.GA22095@elte.hu> References: <4B27702F.1080507@cn.fujitsu.com> <20091215142325.GC5833@nowhere> <4B30C2D1.4030006@cn.fujitsu.com> <4B30C3A0.909@cn.fujitsu.com> <20091228075417.GB20039@elte.hu> <4B3991C1.6060303@cn.fujitsu.com> <1262164786.7135.166.camel@laptop> <20091230092830.GA18190@elte.hu> <1262165789.7135.170.camel@laptop> <1262167566.7135.189.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1262167566.7135.189.camel@laptop> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1144 Lines: 29 * Peter Zijlstra wrote: > OK so there is no sysconf() syscall and its all implemented in glibc, which > is utter suckage.. will have to come up with something saner then. I think integrating it into the perf stream of events would be the most desirable approach - tooling could make use of it easily. For data record (and hierarchy) description /debug/tracing/events/ would be useful. We dont want to actually 'activate' them in an 'event' fashion - but we could use event IDs and the record format and the transport to describe and recover the values. For transport we could use the mmap ring-buffer and it would also be nice to add (or resurrect) some 'quick & easy' read()/write() based transport. It a bit like a value read-out from a counter - just here it's not a regular counter but some sort of kernel-internal value that we want to provide. Hm? Ingo -- 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/