From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E2D1EB64DD for ; Tue, 18 Jul 2023 09:31:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232310AbjGRJa7 (ORCPT ); Tue, 18 Jul 2023 05:30:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232304AbjGRJay (ORCPT ); Tue, 18 Jul 2023 05:30:54 -0400 Received: from szxga01-in.huawei.com (szxga01-in.huawei.com [45.249.212.187]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63234EE; Tue, 18 Jul 2023 02:30:52 -0700 (PDT) Received: from kwepemm600003.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4R4tvz0lPkzrRmk; Tue, 18 Jul 2023 17:30:07 +0800 (CST) Received: from [10.67.111.205] (10.67.111.205) by kwepemm600003.china.huawei.com (7.193.23.202) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.27; Tue, 18 Jul 2023 17:30:49 +0800 Subject: Re: [PATCH v2 5/7] perf evlist: Skip dummy event sample_type check for evlist_config To: Adrian Hunter , , , , , , , , , , , , , , , References: <20230715032915.97146-1-yangjihong1@huawei.com> <20230715032915.97146-6-yangjihong1@huawei.com> <5797e5a7-a85f-4f7c-1649-88f8f9ff7a6b@intel.com> From: Yang Jihong Message-ID: <44645529-0ee6-fe69-bc03-fefbc6f73d4d@huawei.com> Date: Tue, 18 Jul 2023 17:30:48 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.6.1 MIME-Version: 1.0 In-Reply-To: <5797e5a7-a85f-4f7c-1649-88f8f9ff7a6b@intel.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.67.111.205] X-ClientProxiedBy: dggems706-chm.china.huawei.com (10.3.19.183) To kwepemm600003.china.huawei.com (7.193.23.202) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, On 2023/7/17 22:41, Adrian Hunter wrote: > On 15/07/23 06:29, Yang Jihong wrote: >> The dummp event does not contain sampls data. Therefore, sample_type does >> not need to be checked. >> >> Currently, the sample id format of the actual sampling event may be changed >> after the dummy event is added. >> >> Signed-off-by: Yang Jihong >> --- >> tools/perf/util/record.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/tools/perf/util/record.c b/tools/perf/util/record.c >> index 9eb5c6a08999..0240be3b340f 100644 >> --- a/tools/perf/util/record.c >> +++ b/tools/perf/util/record.c >> @@ -128,6 +128,13 @@ void evlist__config(struct evlist *evlist, struct record_opts *opts, struct call >> evlist__for_each_entry(evlist, evsel) { >> if (evsel->core.attr.sample_type == first->core.attr.sample_type) >> continue; >> + >> + /* >> + * Skip the sample_type check for the dummy event >> + * because it does not have any samples anyway. >> + */ >> + if (evsel__is_dummy_event(evsel)) >> + continue; > > Sideband event records have "ID samples" so the sample type still matters. > Okay, will remove this patch in next version. Can I ask a little more about this? Use PERF_SAMPLE_IDENTIFICATION instead of PERF_SAMPLE_ID because for samples of type PERF_RECORD_SAMPLE, there may be different record formats due to different *sample_type* settings, so the fixed SAMPLE_ID location mode PERF_SAMPLE_NAME is required here. However, for the sideband event, the samples of the PERF_RECORD_SAMPLE type is not recorded (only PERF_RECORD_MMAP, PERF_RECORD_COMM, and so on). Therefore, the "use sample identifier "check can be skipped here. That's my understanding of PERF_SAMPLE_IDENTIFICATION . If there is any error, please help to correct it. *Sideband event records have "ID samples" so the sample type still matters.* Does this mean that sideband will also record samples of type PERF_RECORD_SAMPLE? What exactly is the sampling data? Thanks, Yang