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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03DACC2D0E4 for ; Thu, 12 Nov 2020 20:39:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9C8AB21D7F for ; Thu, 12 Nov 2020 20:39:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="DgLA807v" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727134AbgKLUjz (ORCPT ); Thu, 12 Nov 2020 15:39:55 -0500 Received: from mail.kernel.org ([198.145.29.99]:54646 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726566AbgKLUjz (ORCPT ); Thu, 12 Nov 2020 15:39:55 -0500 Received: from quaco.ghostprotocols.net (unknown [179.97.37.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 5B60C216C4; Thu, 12 Nov 2020 20:39:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605213594; bh=HzMiKq9A/i4kjo48D727cdLmgIACBPKIT2rdg3Wsk34=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=DgLA807vDygo60JfvjQM4TBcySje0QzuP7RpTTY06VU8MSpE5bLKzFOVvCAOyze6d mXcdayOOorj6p7T+hO7YNPY8VTpO/H2BH4TRAyA04535ZJXR5Fd/oeAWoMnDO6V+XO jjcIrgmJrSkPhKgyIBkwH9CA2cxKQzheEzdvEGyY= Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 4FB4E411D1; Thu, 12 Nov 2020 17:39:52 -0300 (-03) Date: Thu, 12 Nov 2020 17:39:52 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: Andi Kleen , Jiri Olsa , lkml , Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Song Liu , Ian Rogers , Stephane Eranian , Alexey Budankov , Adrian Hunter Subject: Re: [PATCH 24/24] perf record: Add --buildid-mmap option to enable mmap's build id Message-ID: <20201112203952.GA393548@kernel.org> References: <20201109215415.400153-1-jolsa@kernel.org> <20201109215415.400153-25-jolsa@kernel.org> <20201111170046.GB466880@tassilo.jf.intel.com> <20201112115710.GE619201@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201112115710.GE619201@krava> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Thu, Nov 12, 2020 at 12:57:10PM +0100, Jiri Olsa escreveu: > On Wed, Nov 11, 2020 at 09:00:46AM -0800, Andi Kleen wrote: > > On Mon, Nov 09, 2020 at 10:54:15PM +0100, Jiri Olsa wrote: > > > Adding --buildid-mmap option to enable build id in mmap2 events. > > > It will only work if there's kernel support for that and it disables > > > build id cache (implies --no-buildid). > > What's the point of the option? Why not enable it by default > > if the kernel supports it? > > With the option most user won't get the benefit. > > The only reason I can think of for an option would be to disable > > so that old tools can still process. > yes, that was request in the rfc post, we want the new default > perf.data be still readable by older perf tools We need to change perf so that when it finds some option it doesn't grok, it just ignores extra things in a record like MMAP2 and just warns the user that things are being ignored. So that we can add new stuff by default without requiring an ever longer command line option, like with --all-cgroups, etc. And provide the options to avoid using new stuff if we know that the perf.data file will be processed by someone with an older tool that can't update. - Arnaldo