Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753646AbZG1HWJ (ORCPT ); Tue, 28 Jul 2009 03:22:09 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752004AbZG1HWJ (ORCPT ); Tue, 28 Jul 2009 03:22:09 -0400 Received: from viefep15-int.chello.at ([62.179.121.35]:31548 "EHLO viefep15-int.chello.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751426AbZG1HWI (ORCPT ); Tue, 28 Jul 2009 03:22:08 -0400 X-SourceIP: 213.93.53.227 Subject: Re: [RFC][PATCH 5/5] perfcounter: Add support for kernel hardware breakpoints From: Peter Zijlstra To: Frederic Weisbecker Cc: prasad@linux.vnet.ibm.com, Ingo Molnar , LKML , Steven Rostedt , Thomas Gleixner , Mike Galbraith , Paul Mackerras , Arnaldo Carvalho de Melo , Lai Jiangshan , Anton Blanchard , Li Zefan , Zhaolei , KOSAKI Motohiro , Mathieu Desnoyers , Alan Stern In-Reply-To: <20090728010349.GB5147@nowhere> References: <1248109687-7808-6-git-send-email-fweisbec@gmail.com> <1248354493.26273.2.camel@twins> <1248445569.6987.74.camel@twins> <20090724174723.GA11985@nowhere> <1248519416.5780.12.camel@laptop> <20090725141918.GA5295@nowhere> <1248538972.5780.25.camel@laptop> <20090725235702.GA5082@in.ibm.com> <1248684817.6987.1573.camel@twins> <20090728010349.GB5147@nowhere> Content-Type: text/plain Date: Tue, 28 Jul 2009 09:24:37 +0200 Message-Id: <1248765877.6987.2754.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.26.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 764 Lines: 19 On Tue, 2009-07-28 at 03:03 +0200, Frederic Weisbecker wrote: > > Thirdly, we can multiplex perf counters beyond their hardware maximum, > > something you simply cannot do for a debug interface. > > > Again, I'm stuck in what you mean by multiplexing here :-) If you'd create say 16 breakpoint counters, we'd RR them over the 4 available hardware breakpoints (or less when others are taken by someone else). Since its all statistics anyway, we can simply scale the event counts up by the time-share they received. -- 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/