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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7C636C76195 for ; Fri, 17 Mar 2023 03:51:31 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id F22EE900004; Thu, 16 Mar 2023 23:51:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id ED1DF900002; Thu, 16 Mar 2023 23:51:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC08C900004; Thu, 16 Mar 2023 23:51:30 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id CCDBB900002 for ; Thu, 16 Mar 2023 23:51:30 -0400 (EDT) Received: from smtpin25.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id A1508402F0 for ; Fri, 17 Mar 2023 03:51:30 +0000 (UTC) X-FDA: 80577015540.25.99F10A3 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf24.hostedemail.com (Postfix) with ESMTP id 07A8E180011 for ; Fri, 17 Mar 2023 03:51:28 +0000 (UTC) Authentication-Results: imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="RkgV/CLM"; spf=none (imf24.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1679025089; a=rsa-sha256; cv=none; b=Ozdhje7oeYmpQye0pvgZnSgnN2mlFfy0nanXpnB7/TNeh2qytA1rRocV4pZ9n0nyWGQx7I GY+XMu+TeWax5oEQ6wSVYZaz71I0rhslYPK2tGPN+n+sFtjzlHwsZeqmYlXX6rvFdw+/Z8 WnaKw8FEA0kGhexLT23sj1W60nLyTKo= ARC-Authentication-Results: i=1; imf24.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b="RkgV/CLM"; spf=none (imf24.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1679025089; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=6e5vgV9Lhq/FUovigpv1aQ+kfiWhjBTgyYSzrwszW/M=; b=xCXLkVMhxzcuu/47lMJ+2qEY8SS/oEw6zo0pr804LJ/jYowEuPabAUQ9efpHVN4/kX6sKW pyk3vCfTnpVgFw7bVHjFWnL/qhZ6vNnHbaKbGRD1dQq7JYiuNPTV+RHmEmleDH79z7GCD6 zPX1wJt7Z9bwfX81rk7erox0P9Evcb0= DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=6e5vgV9Lhq/FUovigpv1aQ+kfiWhjBTgyYSzrwszW/M=; b=RkgV/CLM0H4tbM+sMx80KLuyZI dhlobK9j/Zpdl37/xfWN7sk8uzdEF1sMSNimFevN1BOWVS4+VnFHCRMPFNviV6jgqSKr/R2usMGVa RyLURFWSuNiUJOzucNIF0hAkeYzU9Mv2Re4vYNb7wEdkB+7c785k79P1Y2oSmegvz39Apa6v29/kp INL7HuskgHrZmd8pWt7+VcOEHVAcxYKBIdzqIw/z4Pp4Wd1rwUte1cGugOTh9sSNhSfZCfH0ap6wM I/ybbA6jm7zMzvCbNc7/lzIWdoJEP/lWSrKGnDyxaBrNDukTEYb5N6c+blBV4fKli/754t71UzsAT Y6R05JGQ==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pd17b-00FTM7-BU; Fri, 17 Mar 2023 03:51:15 +0000 Date: Fri, 17 Mar 2023 03:51:15 +0000 From: Matthew Wilcox To: Andrii Nakryiko Cc: Ian Rogers , Jiri Olsa , Alexei Starovoitov , Andrii Nakryiko , Hao Luo , Andrew Morton , Alexander Viro , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-perf-users@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Daniel Borkmann , Namhyung Kim , Dave Chinner Subject: Re: [PATCHv3 bpf-next 0/9] mm/bpf/perf: Store build id in file object Message-ID: References: <20230316170149.4106586-1-jolsa@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspam-User: X-Rspamd-Queue-Id: 07A8E180011 X-Rspamd-Server: rspam01 X-Stat-Signature: ypa3c3gyns73ooky7e41qaj3fjahkfhf X-HE-Tag: 1679025088-38771 X-HE-Meta: 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 6moMshKZ xY9tc+vjY6cmpBG9au9jgROTm2dLjdUn/3VTrjLboyCzWXdcWTEujfJRDdLpjX81jHq5Rw+5e+jFvGmALkh1gQVneDEdDvMJVMn7iKgpbTD9hAQXSlbXjbV9BmKX7v7E10s6wH2L3rLVPu2dnRhxTSIo5YxjqqDmMvR0QDqY39qdeNGtoRRgurqCAE6SvC7Kn9kYERNkLUhoJ+kcCYN1gQEWEMo2ZLOoHK7fq X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Mar 16, 2023 at 02:51:52PM -0700, Andrii Nakryiko wrote: > Yep, Meta is also capturing stack traces with build ID as well, if > possible. Build IDs help with profiling short-lived processes which > exit before the profiling session is done and user-space tooling is > able to collect /proc//maps contents (which is what Ian is > referring to here). But also build ID allows to offload more of the > expensive stack symbolization process (converting raw memory addresses > into human readable function+offset+file path+line numbers > information) to dedicated remote servers, by allowing to cache and > reuse preprocessed DWARF/ELF information based on build ID. > > I believe perf tool is also using build ID, so any tool relying on > perf capturing full and complete profiling data for system-wide > performance analysis would benefit as well. > > Generally speaking, there is a whole ecosystem built on top of > assumption that binaries have build ID and profiling tooling is able > to provide more value if those build IDs are more reliably collected. > Which ultimately benefits the entire open-source ecosystem by allowing > people to spot issues (not necessarily just performance, it could be > correctness issues as well) more reliably, fix them, and benefit every > user. But build IDs are _generally_ available. The only problem (AIUI) is when you're trying to examine the contents of one container from another container. And to solve that problem, you're imposing a cost on everybody else with (so far) pretty vague justifications. I really don't like to see you growing struct file for this (nor struct inode, nor struct vm_area_struct). It's all quite unsatisfactory and I don't have a good suggestion.