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=-2.2 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 7A580C04EB8 for ; Mon, 10 Dec 2018 10:18:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4266620821 for ; Mon, 10 Dec 2018 10:18:43 +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="mNJp2Z7p" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4266620821 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 S1727038AbeLJKSm (ORCPT ); Mon, 10 Dec 2018 05:18:42 -0500 Received: from merlin.infradead.org ([205.233.59.134]:56618 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726994AbeLJKSj (ORCPT ); Mon, 10 Dec 2018 05:18:39 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.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=itu9hc9/z9YcrGCrf9vsiWkRxeMGVAIeV48qvUZMUlg=; b=mNJp2Z7pRBP3RW/TTTP3hz6Ga NyHiT+mE4Q9t/sUfSaLIGYt9DTXBqDejpiD1haNGcMsk6z2CZ5UYqPHUnQo0DRlPuBdDG/i9wgqHn x8XqUeOROq+ob3gD0YixmiGEjAnLSteTli+MymAFDq0sYixP9ayNkE97Y86OgZ7nqej1Y0yT0K7jJ Rw699Z24rCYAYWyTSbdih+S2HuqkdSQuJcMBYS+EqDTpcX1WrJpJXSTvmn/Xrkt+eKnpGjEgbky6O OJu4qRg8ubMVNu6yqY8jhqPgvsxX0DxwkTMI8AGQAMLMOg+0U6oZKLTlDjtFnHJNoqGUXFkJE1uaY uVZhWqTcw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gWIdn-0003FW-QR; Mon, 10 Dec 2018 10:18:20 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 292132075A8BB; Mon, 10 Dec 2018 11:18:18 +0100 (CET) Date: Mon, 10 Dec 2018 11:18:18 +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: <20181210101818.GJ5289@hirez.programming.kicks-ass.net> References: <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> <20181208104423.GE5289@hirez.programming.kicks-ass.net> <20181208123805.1c158665@vmware.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181208123805.1c158665@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 Sat, Dec 08, 2018 at 12:38:05PM -0500, Steven Rostedt wrote: > On Sat, 8 Dec 2018 11:44:23 +0100 > Peter Zijlstra wrote: > > > 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. > > Basically you are saying, break strace and see if anyone notices? Nah, give it a new name. Clearly mark this is a new tool. > > > 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. > > If you don't see the use case, I'm not sure anyone can convince you. > Again, I like the fact that when I do a strace of an application I know > that all system calls that the application I'm tracing is recorded. I > don't need to worry about what happened in the "lost events" space. You're the one pushing for this crap without _any_ justification. Why are you getting upset if I ask for some? If people care so much, it shouldn't be hard to write up a coherent story on this, so far all I seem to get is: because it's always been like that. Which really isn't much of an argument.