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=-8.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham 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 1E7ECC433E2 for ; Mon, 14 Sep 2020 22:39:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D1C7620732 for ; Mon, 14 Sep 2020 22:39:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600123143; bh=wjmspuEMssYc9ED3xKlxbWHRGBVIKDlfpMgFfWNfVMI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=gtP0xSRwD0zXGaMMwDQ5xTB0DPX3QppPM/Ot6vyZKw1H9p/6DZ8C6VtWEbNBQoqQv doOSJfp2OTqHPhbDrloZdXDfnzJXNQ0AeQk2GbJg0P0/ZXiYy3GHXNbjRW7Nb3RhTV IAUqVVtiB7UKPoB8iO+rOgOO8Ol9LmgzTgn2AuPI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726067AbgINWjC (ORCPT ); Mon, 14 Sep 2020 18:39:02 -0400 Received: from mail.kernel.org ([198.145.29.99]:57572 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725986AbgINWjB (ORCPT ); Mon, 14 Sep 2020 18:39:01 -0400 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 4E1CE20732; Mon, 14 Sep 2020 22:39:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600123140; bh=wjmspuEMssYc9ED3xKlxbWHRGBVIKDlfpMgFfWNfVMI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hKV6/GRmmwf0SqxcwVp1e/npQy20IVHI/x4VgPzkSaWr6rSwLgRAnuQUvG1/wTjpT /hZMfUF86M8P/p/liRNXAOO0DFk/ed/f3ydUerQPu2wx7iCbCU+67CvYuWS8aqrv7q AICALaZZrtahJeyEz9Nqor9P6c/5HTFZJWo/DpqA= Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 7088F40D3D; Mon, 14 Sep 2020 19:38:58 -0300 (-03) Date: Mon, 14 Sep 2020 19:38:58 -0300 From: Arnaldo Carvalho de Melo To: Jiri Olsa Cc: Stephane Eranian , Jiri Olsa , lkml , Peter Zijlstra , Ingo Molnar , Mark Rutland , Namhyung Kim , Alexander Shishkin , Michael Petlan , Song Liu , "Frank Ch. Eigler" , Ian Rogers , Alexey Budankov , Andi Kleen , Adrian Hunter Subject: Re: [PATCH 02/26] perf: Introduce mmap3 version of mmap event Message-ID: <20200914223858.GL166601@kernel.org> References: <20200913210313.1985612-1-jolsa@kernel.org> <20200913210313.1985612-3-jolsa@kernel.org> <20200914153134.GD160517@kernel.org> <20200914195045.GQ1714160@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200914195045.GQ1714160@krava> X-Url: http://acmel.wordpress.com Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Mon, Sep 14, 2020 at 09:50:45PM +0200, Jiri Olsa escreveu: > On Mon, Sep 14, 2020 at 12:31:34PM -0300, Arnaldo Carvalho de Melo wrote: > > SNIP > > > > > --- > > > > include/uapi/linux/perf_event.h | 27 ++++++++++++++++++++++- > > > > kernel/events/core.c | 38 +++++++++++++++++++++++++++------ > > > > 2 files changed, 57 insertions(+), 8 deletions(-) > > > > > > > > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h > > > > index 077e7ee69e3d..facfc3c673ed 100644 > > > > --- a/include/uapi/linux/perf_event.h > > > > +++ b/include/uapi/linux/perf_event.h > > > > @@ -384,7 +384,8 @@ struct perf_event_attr { > > > > aux_output : 1, /* generate AUX records instead of events */ > > > > cgroup : 1, /* include cgroup events */ > > > > text_poke : 1, /* include text poke events */ > > > > - __reserved_1 : 30; > > > > + mmap3 : 1, /* include bpf events */ > > > > + __reserved_1 : 29; > > > > > > > what happens if I set mmap3 and mmap2? > > > > > > I think using mmap3 for every mmap may be overkill as you add useless > > > 20 bytes to an mmap record. > > > > So use just PERF_RECORD_MMAP2. > > > > I think if the user says: I need buildids, then, in kernels with support > > for getting the buildid in MMAP records, use it as its more accurate, > > otherwise fall back to traversing all records at the end to go over lots > > of files haversting those build-ids. > > ok, so special record option to enable this > > > > > If the user says I don't want build-ids, nothing changes, no collection > > at the end, perf continues using PERF_RECORD_MMAP2. > > and that's -B option in record Yeah, so if -B is used, MMAP2, otherwise, the best available option, which is MMAP3, which by now means more how you tweak the misc bits and what you collect, buildids or just the maj/min/ino :) - Arnaldo > > > > > I am not sure if your code handles the case where mmap3 is not needed > > > because there is no buildid, e.g, anonymous memory. > > > It seems to me you've written the patch in such a way that if the user > > > tool supports mmap3, then it supersedes mmap2, and thus > > > you need all the fields of mmap2. But if could be more interesting to > > > return either MMAP2 or MMAP3 depending on tool support > > > and type of mmap, that would certainly save 20 bytes on any anon mmap. > > > But maybe that logic is already in your patch and I missed it. > > > > Right, it should take into account if the user asked for build-ids or > > not in addition to checking if the kernel supports MMAP3. > > right, thanks, > > jirka > -- - Arnaldo