Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751410Ab2JVH53 (ORCPT ); Mon, 22 Oct 2012 03:57:29 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:48336 "EHLO LGEMRELSE7Q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750910Ab2JVH52 (ORCPT ); Mon, 22 Oct 2012 03:57:28 -0400 X-AuditID: 9c930197-b7c4aae000004160-ff-5084fc65c7ac From: Namhyung Kim To: Jiri Olsa Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Peter Zijlstra , Ingo Molnar , Paul Mackerras , Corey Ashford , Frederic Weisbecker Subject: Re: [PATCH 03/11] perf tool: Use PERF_EVENT_IOC_ID perf ioctl to read event id References: <1350743599-4805-1-git-send-email-jolsa@redhat.com> <1350743599-4805-4-git-send-email-jolsa@redhat.com> Date: Mon, 22 Oct 2012 16:57:24 +0900 In-Reply-To: <1350743599-4805-4-git-send-email-jolsa@redhat.com> (Jiri Olsa's message of "Sat, 20 Oct 2012 16:33:11 +0200") Message-ID: <87ehkrj5wb.fsf@sejong.aot.lge.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1065 Lines: 43 Hi, Just a minor nitpicking.. On Sat, 20 Oct 2012 16:33:11 +0200, Jiri Olsa wrote: > Changing the way we retrieve the event ID. Instead of parsing out > the ID out of the read data, using the PERF_EVENT_IOC_ID ioctl. > > Keeping the old way in place to support kernels without > PERF_EVENT_IOC_ID ioctl support. [snip] > + } else if (errno) > + return -1; Is this check really needed? I think that returning non-zero from the ioctl always sets the errno, no? How about this: ret = ioctl(fd, PERF_EVENT_IOC_ID, &id); if (!ret) goto add; if (errno != ENOTTY) return -1; ... I guess that it'll show you better diff stat. :) Thanks, Namhyung > > - perf_evlist__id_add(evlist, evsel, cpu, thread, read_data[id_idx]); > + add: > + perf_evlist__id_add(evlist, evsel, cpu, thread, id); > return 0; > } -- 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/