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 F242FEB64DA for ; Tue, 18 Jul 2023 10:30:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231303AbjGRKaT (ORCPT ); Tue, 18 Jul 2023 06:30:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40720 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231445AbjGRKaO (ORCPT ); Tue, 18 Jul 2023 06:30:14 -0400 Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4D74DE4F; Tue, 18 Jul 2023 03:30:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689676212; x=1721212212; h=message-id:date:mime-version:subject:to:references:from: in-reply-to:content-transfer-encoding; bh=K+4kNxHQIbdWa/W8bQDdyQh8NM/jPe+65g6OQMfRd/A=; b=DZ8rY9a+JTVbDphI77cTsgG+Vqqlcnpq11FjkEjslGYkizaoS2gzy4xp v2gBdx7TzdS0de4Bw28RtxLHAkXdKAgF3pGWx2lRLuNFJ7AvndH+oRpdE MtJdqae6TrQOnlC0Q+4jokugqwrEHsRJgHqo6VLqcOl5rPULgFL++5ekX End1GZV09POYwTE0finHrOqHLQeYeziDc/S/5BkMCr8KenBqVnOCj8NiF rW2uDrU9ZbFLshNzf+b0x+4StZpJM4+igUn0ARZ77xp8ha13sugymFozz PrpEmot5SvNgVedScHHTP+IcmWQT7ErUdkWzSRMQc8L0pJP0Ma3gkJWiN g==; X-IronPort-AV: E=McAfee;i="6600,9927,10774"; a="452548376" X-IronPort-AV: E=Sophos;i="6.01,214,1684825200"; d="scan'208";a="452548376" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jul 2023 03:30:08 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10774"; a="793586273" X-IronPort-AV: E=Sophos;i="6.01,214,1684825200"; d="scan'208";a="793586273" Received: from ahunter6-mobl1.ger.corp.intel.com (HELO [10.0.2.15]) ([10.251.223.138]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Jul 2023 03:30:03 -0700 Message-ID: Date: Tue, 18 Jul 2023 13:29:57 +0300 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Firefox/102.0 Thunderbird/102.13.0 Subject: Re: [PATCH v2 5/7] perf evlist: Skip dummy event sample_type check for evlist_config Content-Language: en-US To: Yang Jihong , peterz@infradead.org, mingo@redhat.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, kan.liang@linux.intel.com, james.clark@arm.com, tmricht@linux.ibm.com, ak@linux.intel.com, anshuman.khandual@arm.com, linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org References: <20230715032915.97146-1-yangjihong1@huawei.com> <20230715032915.97146-6-yangjihong1@huawei.com> <5797e5a7-a85f-4f7c-1649-88f8f9ff7a6b@intel.com> <44645529-0ee6-fe69-bc03-fefbc6f73d4d@huawei.com> <77ea9309-da6f-f7b9-a822-b371e0f832d3@huawei.com> From: Adrian Hunter Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki, Business Identity Code: 0357606 - 4, Domiciled in Helsinki In-Reply-To: <77ea9309-da6f-f7b9-a822-b371e0f832d3@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 18/07/23 13:17, Yang Jihong wrote: > Hello, > > On 2023/7/18 17:56, Adrian Hunter wrote: >> On 18/07/23 12:30, Yang Jihong wrote: >>> 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? >> >> No.  There are additional members as defined by struct sample_id for PERF_RECORD_MMAP: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/uapi/linux/perf_event.h?h=v6.4#n872 >> > I'm sorry, maybe my comments didn't make it clear. > I mean, can we skip the "use_sample_identifier" check here? > > That is, set sample_type to *XXX|PERF_SAMPLE_ID* instead of *XXX|PERF_SAMPLE_IDENTIFICATION* In general, when there are different values of sample_type, the PERF_SAMPLE_ID is needed to determine which is which. But PERF_SAMPLE_ID is not at a fixed position, so the sample_type is needed to find it. That is why PERF_SAMPLE_IDENTIFIER is better. Why do want to change it?