Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759661Ab3DYXT0 (ORCPT ); Thu, 25 Apr 2013 19:19:26 -0400 Received: from mail-db8lp0185.outbound.messaging.microsoft.com ([213.199.154.185]:45476 "EHLO db8outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758214Ab3DYXTY (ORCPT ); Thu, 25 Apr 2013 19:19:24 -0400 X-Forefront-Antispam-Report: CIP:163.181.249.109;KIP:(null);UIP:(null);IPV:NLI;H:ausb3twp02.amd.com;RD:none;EFVD:NLI X-SpamScore: -4 X-BigFish: VPS-4(zzbb2dI98dI9371I1432Izz1f42h1fc6h1ee6h1de0h1fdah1202h1e76h1d1ah1d2ahzzz2dh668h839h944hd25hd2bhf0ah1220h1288h12a5h12a9h12bdh137ah13b6h1441h1504h1537h153bh162dh1631h1758h18e1h1946h19b5h1ad9h1b0ah1d0ch1155h) X-WSS-ID: 0MLU3FZ-02-DE7-02 X-M-MSG: Date: Thu, 25 Apr 2013 18:19:11 -0500 From: Jacob Shin To: "H. Peter Anvin" CC: Oleg Nesterov , Will Deacon , Ingo Molnar , Frederic Weisbecker , Peter Zijlstra , Arnaldo Carvalho de Melo , Thomas Gleixner , "x86@kernel.org" , Stephane Eranian , Jiri Olsa , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH V2 1/4] perf: Add hardware breakpoint address mask Message-ID: <20130425231911.GB31751@jshin-Toonie> References: <1366703825-19373-2-git-send-email-jacob.shin@amd.com> <20130423095437.GD17593@mudshark.cambridge.arm.com> <20130423143423.GB17021@jshin-Toonie> <20130423144057.GA19644@jshin-Toonie> <20130423150240.GD18616@mudshark.cambridge.arm.com> <20130423151846.GA22052@jshin-Toonie> <20130424094853.GB21850@mudshark.cambridge.arm.com> <20130424163038.GA29816@jshin-Toonie> <20130425170635.GA1324@redhat.com> <5179652F.8080507@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <5179652F.8080507@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginatorOrg: amd.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1557 Lines: 51 On Thu, Apr 25, 2013 at 10:17:35AM -0700, H. Peter Anvin wrote: > On 04/25/2013 10:06 AM, Oleg Nesterov wrote: > >> > >> The downside is that in userland perf tool we need differing documentation > >> on what the mask syntax means for each architecture. > > > > Personally I think this is acceptable. > > > > But I am new to this code, so... > > > > That would seem really, really awkward. Yes, perf has a bunch of > low-level stuff, but it would seem highly undesirable to force the user > to deal with something like that. > > It would be good to have a user-friendly syntax that covers most of what > users may want to do and perhaps a longer form that can express > everything including ARM's byte selects; if the system can't honor the > request it should return an error. Okay, If arch specific masks are a no go, then I think I'm convinced that Oleg's idea of using bp_len is the right thing to do. Right now perf userland tool hard codes bp_len to 4, so I need to modify it to allow user to override the length if desired. Oleg, Frederic, et al. Which syntax do you prefer? If we want to set bp_len to 16: $ perf stat -e mem:0x1000:rw:16 Or $ perf stat -e mem:0x1000:16 Or $ perf stat -e mem:0x1000/16 If no bp_len value is specified, it will still default to 4 as it did before. -- 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/