Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755884Ab0AVQxN (ORCPT ); Fri, 22 Jan 2010 11:53:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755482Ab0AVQxM (ORCPT ); Fri, 22 Jan 2010 11:53:12 -0500 Received: from bombadil.infradead.org ([18.85.46.34]:57085 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751710Ab0AVQxH (ORCPT ); Fri, 22 Jan 2010 11:53:07 -0500 Subject: Re: [PATCH 00/12] perf lock: New subcommand "perf lock", for analyzing lock statistics From: Peter Zijlstra To: Jason Baron Cc: Hitoshi Mitake , Ingo Molnar , linux-kernel@vger.kernel.org, Paul Mackerras , Tom Zanussi , Steven Rostedt , Thomas Gleixner , Greg Kroah-Hartman In-Reply-To: <1264178909.4283.1543.camel@laptop> References: <1264167553-6510-1-git-send-email-mitake@dcl.info.waseda.ac.jp> <20100122164248.GA2651@redhat.com> <1264178909.4283.1543.camel@laptop> Content-Type: text/plain; charset="UTF-8" Date: Fri, 22 Jan 2010 17:52:49 +0100 Message-ID: <1264179169.4283.1545.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1419 Lines: 31 On Fri, 2010-01-22 at 17:48 +0100, Peter Zijlstra wrote: > On Fri, 2010-01-22 at 11:42 -0500, Jason Baron wrote: > > On Fri, Jan 22, 2010 at 10:39:01PM +0900, Hitoshi Mitake wrote: > > > Adding new subcommand "perf lock" to perf. > > > > > > > looks like a really intresting patch! Does this patch mean that we can > > potentially remove CONFIG_LOCK_STAT, now that the functionality is > > available via 'perf'? Another desire for me has been to able to run > > lockstat on production box. This has not been possible before without > > incurring the performance penalty of lockdep. however, with 'perf' tools > > ability to be turned on an off, perhaps there is (or we can build) a > > mode for lockdep that is lower overhead for this usecase? > > boot with: prove_locking=0 > > This patch still needs all the hooks and bits from lockdep, no way you > want all that in a prodction kernel. Also, I suspect lockstat to still be lots faster, since it doesn't need to transfer gobs of data but builds the histogram in-kernel. Having the ability to do in-kernel histrograms with perf is something I've thought about but not yet managed to think of a nice way of doing it. -- 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/