From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755947Ab2FPG7P (ORCPT ); Sat, 16 Jun 2012 02:59:15 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:52432 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755737Ab2FPG7O (ORCPT ); Sat, 16 Jun 2012 02:59:14 -0400 Date: Sat, 16 Jun 2012 08:59:03 +0200 From: Ingo Molnar To: Greg Kroah-Hartman Cc: Fengguang Wu , Steven Rostedt , LKML , Linus Torvalds , "kay.sievers" , "Paul E. McKenney" , Ingo Molnar , Andrew Morton Subject: Re: [PATCH] printk: Add printk_flush() to force buffered text to console Message-ID: <20120616065903.GA24594@gmail.com> References: <1339649173.13377.191.camel@gandalf.stny.rr.com> <20120614045930.GA10508@kroah.com> <1339671715.13377.209.camel@gandalf.stny.rr.com> <20120614154153.GD17140@kroah.com> <1339693625.13377.242.camel@gandalf.stny.rr.com> <20120615042233.GA10973@localhost> <20120615043017.GA9587@kroah.com> <20120615120430.GB23681@gmail.com> <20120615231318.GD8205@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120615231318.GD8205@kroah.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Greg Kroah-Hartman wrote: > On Fri, Jun 15, 2012 at 02:04:30PM +0200, Ingo Molnar wrote: > > > > * Greg Kroah-Hartman wrote: > > > > > On Fri, Jun 15, 2012 at 12:22:33PM +0800, Fengguang Wu wrote: > > > > > I actually would like to make these more compact. As all my test box > > > > > consoles go through serial ports, just booting through this takes more > > > > > time the the compile itself. > > > > > > > > The tests took 23 seconds boot time on one kernel: > > > > > > > > [ 0.152934] Testing tracer nop: PASSED > > > > ...1577 lines total... > > > > [ 23.206550] Testing kprobe tracing: OK > > > > > > > > And 135 seconds in another bloated kernel: > > > > > > > > [ 115.396441] Testing event 9p_client_req: OK > > > > ...2545 lines total... > > > > [ 240.268783] Testing kprobe tracing: OK > > > > > > > > I'd appreciate if the boot time can be reduced. Because I'm doing > > > > kernel boot tests for *every single* commits. > > > > > > > > It may look insane amount of work, but it's still manageable: with 10 > > > > kvm instances each take 1 minute to boot test a kernel, I can boot > > > > test 60*24*10=14400 kernels in one day. That's a rather big number. > > > > That allows me to run more cpu/vm/io stress tests for each kernel :-) > > > > > > Do you really want to enable those tests for your test > > > kernels? Can they fail if we mess up other parts of the > > > kernel, or do they only test the tracing portions? > > > > These printk's are useful, are used for a specific (albeit > > limited) purpose and were and continue to be useful in that > > role. > > > > The changes Steve bisected to broke this use of printk(). > > And note, fixed others :) Sorry, the "we fix some bugs and introduce others" stance is not a valid response to a regression. Either fix *all* regressions or revert the original change. Simple and robust policy, isn't it? > > Please apply Steve's fix, fix it yourself or revert the > > changes that regressed printk(). > > I thought Steve's patch was just a RFC thing, is it really > something that everyone wants to see applied? You mean the adding of an API to flush buffered output when that's the desired outcome? Why the heck should we *not* want that? Either I'm the weird one or you are being difficult ;-) Thanks, Ingo