Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755364AbdLOLXV (ORCPT ); Fri, 15 Dec 2017 06:23:21 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:41739 "EHLO huawei.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1753279AbdLOLXS (ORCPT ); Fri, 15 Dec 2017 06:23:18 -0500 Subject: Re: [RFC PATCH 2/5] perf jevents: add support for arch recommended events To: Jiri Olsa References: <1512490399-94107-1-git-send-email-john.garry@huawei.com> <1512490399-94107-3-git-send-email-john.garry@huawei.com> <20171206133607.GA12508@krava> <20171208122918.GE2799@krava> <20171209073104.GB14297@krava> CC: , , , , , , , , , , , , , , , From: John Garry Message-ID: <5d322353-2785-a99f-bcd8-b948bd6cb09a@huawei.com> Date: Fri, 15 Dec 2017 11:22:50 +0000 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20171209073104.GB14297@krava> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.238] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2188 Lines: 56 >> Actually having a scalable JSON standard format for pmu events, which allows >> us to define common events per architecture / vendor and reference them per >> platform JSON could be useful. >> >> Here we're dealing with trade-off between duplication (simplicity) vs >> complexity (or over-engineering). > > understood, but as I said we already are ok with duplicates, > if it's reasonable size as is for x86 now.. how much amount > are we talking about for arm? > Hi Jirka, When you say reasonable size for x86, I ran a string duplication finder on the x86 JSONs and the results show a huge amount of duplication. Please check this: https://gist.githubusercontent.com/johnpgarry/68bc87e823ae2ce0f7b475b4e55e5795/raw/f4cea138999d8b34151b9586d733592e01774d7a/x86%2520JSON%2520duplication Extract: "Found a 65 line (311 tokens) duplication in the following files: Starting at line 100 of /linux/tools/perf/pmu-events/arch/x86/ivybridge/ivb-metrics.json Starting at line 100 of /linux/tools/perf/pmu-events/arch/x86/ivytown/ivt-metrics.json Starting at line 100 of /linux/tools/perf/pmu-events/arch/x86/broadwell/bdw-metrics.json Starting at line 100 of /linux/tools/perf/pmu-events/arch/x86/skylakex/skx-metrics.json Starting at line 76 of /linux/tools/perf/pmu-events/arch/x86/jaketown/jkt-metrics.json Starting at line 100 of /linux/tools/perf/pmu-events/arch/x86/skylake/skl-metrics.json Starting at line 76 of /linux/tools/perf/pmu-events/arch/x86/sandybridge/snb-metrics.json Starting at line 100 of /linux/tools/perf/pmu-events/arch/x86/broadwellx/bdx-metrics.json" Won't this all potentially have a big maintainence cost? For example, I saw multiple JSON update patches which look identical: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/tools/perf/pmu-events/arch/x86?h=v4.15-rc3&id=7347bba5552f479d4292ffd008d18d41a965f021 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/tools/perf/pmu-events/arch/x86?h=v4.15-rc3&id=984d91f4c62f64026cbfef51f609971025934cec I just don't know how this schema scales with more archs and more platforms supported. It's just early days now... Regards, John > jirka > > . >