Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754293Ab0HCIBF (ORCPT ); Tue, 3 Aug 2010 04:01:05 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:33742 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754194Ab0HCIBA convert rfc822-to-8bit (ORCPT ); Tue, 3 Aug 2010 04:01:00 -0400 Subject: Re: [PATCH RFC] perf lock: Add new event "lock_acquired_waittime" for contention analysis From: Peter Zijlstra To: Hitoshi Mitake Cc: Frederic Weisbecker , Steven Rostedt , linux-kernel@vger.kernel.org, h.mitake@gmail.com, Ingo Molnar , Paul Mackerras , Arnaldo Carvalho de Melo , Jason Baron , Xiao Guangrong , Jens Axboe In-Reply-To: <4C57C72C.3070902@dcl.info.waseda.ac.jp> References: <1279990529-8798-1-git-send-email-mitake@dcl.info.waseda.ac.jp> <20100728163946.GB5394@nowhere> <4C5507F2.7090503@dcl.info.waseda.ac.jp> <1280751784.1923.146.camel@laptop> <4C57C72C.3070902@dcl.info.waseda.ac.jp> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Tue, 03 Aug 2010 10:00:40 +0200 Message-ID: <1280822440.1923.403.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 964 Lines: 23 On Tue, 2010-08-03 at 16:37 +0900, Hitoshi Mitake wrote: > But, I believe that > - lock validation > - lock tracing > - in kernel light weight lock usage statistics > should be divided into individual features, at least. > And tracing and statistics should be available for production kernel, > ideally. > > How do you think about this point? Both the lock usage and lock validation use the lock classification scheme and thus require the bloated lock structures, and hence I don't think its at all reasonable to do that runtime. lock tracing could possibly be done by patching all lock sites, but we'd have to be somewhat careful there too not to make the whole spinlock code even worse than it already is. -- 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/