From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751998AbaL3FuJ (ORCPT ); Tue, 30 Dec 2014 00:50:09 -0500 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:33735 "EHLO lgemrelse7q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751779AbaL3FuH (ORCPT ); Tue, 30 Dec 2014 00:50:07 -0500 X-Original-SENDERIP: 10.177.222.235 X-Original-MAILFROM: namhyung@kernel.org Date: Tue, 30 Dec 2014 14:51:11 +0900 From: Namhyung Kim To: Adrian Hunter Cc: David Ahern , Arnaldo Carvalho de Melo , Ingo Molnar , Peter Zijlstra , Jiri Olsa , LKML , Stephane Eranian , Andi Kleen , Frederic Weisbecker Subject: Re: [PATCH 02/37] perf record: Use a software dummy event to track task/mmap events Message-ID: <20141230055111.GE6081@sejong> References: <1419405333-27952-1-git-send-email-namhyung@kernel.org> <1419405333-27952-3-git-send-email-namhyung@kernel.org> <549D8C59.1000700@gmail.com> <54A14FE4.9070601@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <54A14FE4.9070601@intel.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Adrian, On Mon, Dec 29, 2014 at 02:58:12PM +0200, Adrian Hunter wrote: > On 27/12/14 07:28, Namhyung Kim wrote: > > Hi David, > > > > On Sat, Dec 27, 2014 at 1:27 AM, David Ahern wrote: > >> On 12/24/14 12:14 AM, Namhyung Kim wrote: > >>> > >>> Prepend a software dummy event into evlist to track task/comm/mmap > >>> events separately. This is a preparation of multi-file/thread support > >>> which will come later. > >> > >> > >> Are you are making this the first event because of how perf internals are > >> coded -- that the first event tracks tasks events? With the tracking bit in > >> evsel you should not need to do that. Is there another reason? > > > > Yeah, I know the tracking bit can be set to any evsel in the evlist. > > But I'd like to keep it at a fixed index so that it can be easily > > identified at later stages (like perf report) too. Ideally, it'd be > > great if we have a way to distinguish this auto-added dummy tracking > > event from other (user-added) (dummy?) tracking events if any. > > > >> > >> ---8<--- > >> > >>> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c > >>> index cfbe2b99b9aa..72dff295237e 100644 > >>> --- a/tools/perf/util/evlist.c > >>> +++ b/tools/perf/util/evlist.c > >>> @@ -193,6 +193,44 @@ int perf_evlist__add_default(struct perf_evlist > >>> *evlist) > >>> return -ENOMEM; > >>> } > >>> > >>> +int perf_evlist__prepend_dummy(struct perf_evlist *evlist) > >>> +{ > >>> + struct perf_event_attr attr = { > >>> + .type = PERF_TYPE_SOFTWARE, > >>> + .config = PERF_COUNT_SW_DUMMY, > > Probably need .exclude_kernel = 1, here Ah, right. > > >>> + }; > >>> + struct perf_evsel *evsel, *pos; > >>> + > >>> + event_attr_init(&attr); > >>> + > >>> + evsel = perf_evsel__new(&attr); > >>> + if (evsel == NULL) > >>> + goto error; > >>> + > >>> + /* use strdup() because free(evsel) assumes name is allocated */ > >>> + evsel->name = strdup("dummy"); > >>> + if (!evsel->name) > >>> + goto error_free; > >>> + > >>> + list_for_each_entry(pos, &evlist->entries, node) { > >>> + pos->idx += 1; > >>> + pos->tracking = false; > >>> + } > >>> + > >>> + list_add(&evsel->node, &evlist->entries); > >>> + evsel->idx = 0; > >>> + evsel->tracking = true; > >> > >> > >> perf_evlist__set_tracking_event()? > > > > I found that after I wrote this, so yes, it can use the function > > instead of the oped-code. But the loop traversal is needed anyway to > > fixup the evsel->idx. > > perf_evlist__set_tracking_event() also ensures there is only one tracking > event so it is easy to identify. It is the only event with attr->mmap etc > set to 1. Then you can use perf_evlist__add(). Well, yes, I think we can put the dummy tracking event anywhere in the evlist with this, but I still slightly prefer put it at a fixed location for a possible code simplification.. Thanks, Namhyung