Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759434Ab2FULsM (ORCPT ); Thu, 21 Jun 2012 07:48:12 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:60152 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759416Ab2FULsL (ORCPT ); Thu, 21 Jun 2012 07:48:11 -0400 MIME-Version: 1.0 In-Reply-To: <1340278853.21745.178.camel@twins> References: <1339741902-8449-1-git-send-email-zheng.z.yan@intel.com> <1340208092.21745.114.camel@twins> <4FE28823.80704@intel.com> <4FE2DE9A.70202@intel.com> <1340278853.21745.178.camel@twins> Date: Thu, 21 Jun 2012 13:48:09 +0200 Message-ID: Subject: Re: [PATCH V6 0/13] perf: Intel uncore pmu counting support From: Stephane Eranian To: Peter Zijlstra Cc: "Yan, Zheng" , mingo@elte.hu, jolsa@redhat.com, andi@firstfloor.org, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo Content-Type: text/plain; charset=UTF-8 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1705 Lines: 40 On Thu, Jun 21, 2012 at 1:40 PM, Peter Zijlstra wrote: > On Thu, 2012-06-21 at 11:13 +0200, Stephane Eranian wrote: > >> >>> How about treat the 'cpu' parameter for uncore event as socket id instead >> >>> of cpu id? >> >>> >> >> But that does not address the use case of Peter, i.e., no cpu parameter passed. >> >> Looks like sysfs might be the only way to do this in a portable manner. >> >> >> > It does. For example, on a dual socket system, perf can only register uncore >> > counter with 'cpu' parameter is equal to 0 or 1. This method is hacky, but it >> > requires minimal change for the kernel and perf tool. >> > >> I was saying, I don't want to have to pass -C x with -a and yet have perf stat >> only instantiate the event once per socket. I think that's what PeterZ was >> asking about. > > What Zheng is saying is that -a will iterate [0..nr_cpus), but since > we're interpreting the sys_perf_event_open(.cpu) argument as node, we'll > fail the syscall with -EINVAL or so for .cpu >= nr_node_ids. > Ok, but how do you distinguish EINVAL is this case from an error with a non uncore event? Unless you return a unique error code, I don't see how you'd solve that. In general, I don't like it when perf switches events or CPUs under the cover. When happens with -a -A? > This way, we'll only create one counter per node. > > I would work, but its not pretty since we still don't know what we're > iterating. Not pretty. -- 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/