From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756821AbbJVHaY (ORCPT ); Thu, 22 Oct 2015 03:30:24 -0400 Received: from szxga01-in.huawei.com ([58.251.152.64]:41488 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751967AbbJVHaX (ORCPT ); Thu, 22 Oct 2015 03:30:23 -0400 Message-ID: <5628904C.2040608@huawei.com> Date: Thu, 22 Oct 2015 15:29:16 +0800 From: "Wangnan (F)" User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: Namhyung Kim CC: Arnaldo Carvalho de Melo , Alexei Starovoitov , Brendan Gregg , Peter Zijlstra , Daniel Borkmann , David Ahern , He Kuang , Jiri Olsa , Li Zefan , Masami Hiramatsu , Paul Mackerras , "linux-kernel@vger.kernel.org" , pi3orama , xiakaixu 00238161 , "Arnaldo Carvalho de Melo" Subject: Re: [PATCH 26/31] perf tools: Support perf event alias name References: <1444826502-49291-1-git-send-email-wangnan0@huawei.com> <1444826502-49291-27-git-send-email-wangnan0@huawei.com> <20151021085353.GJ628@sejong> <56278C5E.2060208@huawei.com> In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.111.66.109] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2015/10/22 15:16, Namhyung Kim wrote: > Hi, > > On Wed, Oct 21, 2015 at 10:00 PM, Wangnan (F) wrote: >> >> On 2015/10/21 16:53, Namhyung Kim wrote: >>> Hi, >>> >>> On Wed, Oct 14, 2015 at 12:41:37PM +0000, Wang Nan wrote: >>>> From: He Kuang >>>> >>>> This patch adds new bison rules for specifying an alias name to a perf >>>> event, which allows cmdline refer to previous defined perf event through >>>> its name. With this patch user can give alias name to a perf event using >>>> following cmdline: >>>> >>>> # perf record -e mypmu=cycles ... >>>> >>>> To allow parser refer to existing event selecter, pass event list to >>>> 'struct parse_events_evlist'. perf_evlist__find_evsel_by_alias() is >>>> introduced to get evsel through its alias. >>> What about using event name directly? I guess the alias name is used >>> only to refer an event so it'd be better to use the event name. >>> Anyway we need alias as well when event has no name or name is complex. >> >> It is possible to trigger two perf events with same PMU but >> different config options: >> >> # perf record -e cycles/period=9999/ -e cycles/period=99999/ -a sleep 1 >> >> In this case the name of events are: >> >> cycles/period=9999/ ` >> cycles/period=99999/ >> >> Using it in perf cmdline is painful: >> >> # perf record -e cycles/period=9999/ -e cycles/period=99999/ -e >> bpf_program.c/myevent=cycles/period=9999//... > I understand the need of using aliases but I think it's more natural > to use event name for simple cases.. I will consider this. However, if we allow using event name directly like this: # perf record -e cycles -e test_pmu.c/myevent=cycles/ ... Then two '-e' seems redundant, right? Why not directly using: # perf record -e test_pmu.c/myevent=cycles/ ... and make perf creates cycles event for test_pmu.c? We can make syntax like # perf record -e test_pmu.c/myevent=cycles/ ... as a syntax sugar of # perf record -e randomname=cycles -e test_pmu.c/myevent=randomname/ ... and don't need to find evsel through their names if alias not exist. So this is a new feature, and worth another patch. Thought? > Thanks, > Namhyung