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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT 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 4DA65C04EB8 for ; Sat, 8 Dec 2018 10:44:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 09ADC2082D for ; Sat, 8 Dec 2018 10:44:31 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="JjpzWuMR" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 09ADC2082D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726160AbeLHKoa (ORCPT ); Sat, 8 Dec 2018 05:44:30 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:38690 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726111AbeLHKo3 (ORCPT ); Sat, 8 Dec 2018 05:44:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Wtnpj+V4bXR6i59tlZfOVpAx4HX14ogX7voqGyFBYB0=; b=JjpzWuMR66L7oA5fL9jWbjTeQ 9i2uJU9qpCvzKNkfuy9QBi2Qqlia/EvFSr4fYhPVd/DfGq2FaZSA8bqz2+D0vyzlvRXOA0EZJs+6N KysdE9Zf+gbFcywRgxm7hs86oGpR5IqfnzUCsRS5YEtcVqzfMq/vy7BWDWmaAOfPuJLq1lNXvz+6u QlbbXYZKtBPQpH1/ltf2GcDnlxF0t2KrGuOVvcM7V3MeICOqylmFKhsOdEMzz5gpMP3JBl6m8PZaT kYdQm4bM0C8J6dj6aKVgfSxTt4yb6WPBNvXhsIaRd+anK6vF8PmonrYc+Gvy2fOqr7qMOJCYYEDq9 jpMxqzKzA==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gVa5x-0002hG-5B; Sat, 08 Dec 2018 10:44:25 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id A9996200C3E0F; Sat, 8 Dec 2018 11:44:23 +0100 (CET) Date: Sat, 8 Dec 2018 11:44:23 +0100 From: Peter Zijlstra To: Steven Rostedt Cc: Jiri Olsa , Arnaldo Carvalho de Melo , lkml , Ingo Molnar , Namhyung Kim , Alexander Shishkin , Thomas Gleixner , "Luis Claudio R. Goncalves" , ldv@altlinux.org, esyr@redhat.com, Frederic Weisbecker Subject: Re: [PATCH 1/8] perf: Allow to block process in syscall tracepoints Message-ID: <20181208104423.GE5289@hirez.programming.kicks-ass.net> References: <20181205160509.1168-1-jolsa@kernel.org> <20181205160509.1168-2-jolsa@kernel.org> <20181206081028.GE4234@hirez.programming.kicks-ass.net> <20181206083400.GA13675@hirez.programming.kicks-ass.net> <20181206131946.2c47f556@vmware.local.home> <20181207085839.GC2237@hirez.programming.kicks-ass.net> <20181207072701.5bc564c7@vmware.local.home> <20181207151105.GB5289@hirez.programming.kicks-ass.net> <20181207151433.20bf0399@vmware.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181207151433.20bf0399@vmware.local.home> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 07, 2018 at 03:14:33PM -0500, Steven Rostedt wrote: > On Fri, 7 Dec 2018 16:11:05 +0100 > Peter Zijlstra wrote: > > > On Fri, Dec 07, 2018 at 08:41:18AM -0500, Steven Rostedt wrote: > > > On Fri, 7 Dec 2018 09:58:39 +0100 > > > Peter Zijlstra wrote: > > > > > > > These patches give no justification *what*so*ever* for why we're doing > > > > ugly arse things like this. And why does this, whatever this is, need to > > > > be done in perf? > > > > > > > > IOW, what problem are we solving ? > > > > > > I guess the cover letter should have had a link (or copy) of this: > > > > > > http://lkml.kernel.org/r/20181128134700.212ed035@gandalf.local.home > > > > That doesn't even begin to explain. Who cares about strace and why? And > > why is it such a bad thing to loose the occasional record etc.. > > Who cares about strace? Do I really need to answer that? It's one of > the most used tools for seeing what a program is doing. It's a tool I haven't used in years, given we have so many better tools around these days. > Why do we care about lost events? Because strace records *all* events, > as that's what it does and that's what it always has done. It would be > a break in functionality (a regression) if it were to start losing > events. I use strace to see everything that an application is doing. So make a new tool; break the expectation of all events. See if there's anybody that really cares. > When we discussed this at plumbers, Oracle people came to me and said > how awesome it would be to run strace against their database accesses. > The problem today is that strace causes such a large overhead that it > isn't feasible to trace any high speed applications, especially if > there are time restraints involved. So have them run that perf thing acme pointed to. So far nobody's made a good argument for why we cannot have LOST events.