From mboxrd@z Thu Jan 1 00:00:00 1970 From: john.garry@huawei.com (John Garry) Date: Fri, 15 Dec 2017 11:22:50 +0000 Subject: [RFC PATCH 2/5] perf jevents: add support for arch recommended events In-Reply-To: <20171209073104.GB14297@krava> 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> Message-ID: <5d322353-2785-a99f-bcd8-b948bd6cb09a@huawei.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org >> 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 > > . >