Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752566AbbEGOVa (ORCPT ); Thu, 7 May 2015 10:21:30 -0400 Received: from casper.infradead.org ([85.118.1.10]:59256 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751407AbbEGOV2 (ORCPT ); Thu, 7 May 2015 10:21:28 -0400 Date: Thu, 7 May 2015 11:21:20 -0300 From: Arnaldo Carvalho de Melo To: Peter Zijlstra Cc: Kan Liang , mingo@kernel.org, eranian@google.com, andi@firstfloor.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH V8 7/8] perf, x86: introduce PERF_RECORD_LOST_SAMPLES Message-ID: <20150507142120.GD7862@kernel.org> References: <1430940834-8964-1-git-send-email-kan.liang@intel.com> <1430940834-8964-8-git-send-email-kan.liang@intel.com> <20150507113524.GG23123@twins.programming.kicks-ass.net> <20150507115446.GD16478@twins.programming.kicks-ass.net> <20150507141520.GC7862@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150507141520.GC7862@kernel.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.23 (2014-03-12) X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2219 Lines: 54 Em Thu, May 07, 2015 at 11:15:20AM -0300, Arnaldo Carvalho de Melo escreveu: > Em Thu, May 07, 2015 at 01:54:46PM +0200, Peter Zijlstra escreveu: > > On Thu, May 07, 2015 at 01:35:24PM +0200, Peter Zijlstra wrote: > > > > > > - dropped the @id field from the record, it is already included in the > > > @sample_id values. > > > > Hmm, this would force people to use sample_id; which in general is a > > good idea, but should we really force that on people? > > Well, if there are more than one sample, we need it, right? If there is > just one, we don't need it, what is different? Am I needing (even more) > coffee? > > /me goes read some code... I.e.: [acme@ssdandy linux]$ perf record -e cycles usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.013 MB perf.data (8 samples) ] [acme@ssdandy linux]$ [acme@ssdandy linux]$ perf evlist -v cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|PERIOD, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 [acme@ssdandy linux]$ Just one event, no need for PERF_SAMPLE_ID. But with > 1 events: [acme@ssdandy linux]$ perf record -e cycles,instructions usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.014 MB perf.data (8 samples) ] [acme@ssdandy linux]$ perf evlist -v cycles: size: 112, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|PERIOD, read_format: ID, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1 instructions: size: 112, config: 1, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|ID|PERIOD, read_format: ID, disabled: 1, inherit: 1, freq: 1, enable_on_exec: 1, sample_id_all: 1, exclude_guest: 1 [acme@ssdandy linux]$ - Arnaldo -- 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/