From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753589AbcKPOZu (ORCPT ); Wed, 16 Nov 2016 09:25:50 -0500 Received: from smtprelay0016.hostedemail.com ([216.40.44.16]:45996 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751277AbcKPOZr (ORCPT ); Wed, 16 Nov 2016 09:25:47 -0500 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Spam-Summary: 2,0,0,,d41d8cd98f00b204,rostedt@goodmis.org,:::::::::::::::,RULES_HIT:41:355:379:541:599:800:960:973:988:989:1260:1277:1311:1313:1314:1345:1359:1437:1515:1516:1518:1534:1540:1593:1594:1711:1730:1747:1777:1792:2393:2553:2559:2562:2693:3138:3139:3140:3141:3142:3352:3622:3865:3866:3867:3868:3870:3871:3872:3873:3874:4361:5007:6261:7875:10004:10400:10848:10967:11232:11658:11914:12663:12740:12760:13069:13161:13180:13229:13311:13357:13439:14096:14097:14181:14659:14721:21080:21326:21433:30012:30026:30054:30090:30091,0,RBL:none,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fn,MSBL:0,DNSBL:none,Custom_rules:0:0:0,LFtime:2,LUA_SUMMARY:none X-HE-Tag: jelly45_323b2dc22b849 X-Filterd-Recvd-Size: 1977 Date: Wed, 16 Nov 2016 09:25:43 -0500 From: Steven Rostedt To: Peter Zijlstra Cc: Christoph Lameter , Daniel Vacek , Daniel Bristot de Oliveira , Tommaso Cucinotta , LKML , linux-rt-users , Ingo Molnar Subject: Re: your mail Message-ID: <20161116092543.663e1d2c@gandalf.local.home> In-Reply-To: <20161116104014.GQ3142@twins.programming.kicks-ass.net> References: <20161116104014.GQ3142@twins.programming.kicks-ass.net> X-Mailer: Claws Mail 3.14.0 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 16 Nov 2016 11:40:14 +0100 Peter Zijlstra wrote: > On top of which, the implementation had issues; now I know you're the > blinder kind of person that disregards everything not in his immediate > interest, but if you'd looked at the patch you'd have seen he'd added > code the idle entry path, which will slow down every single to-idle > transition. Isn't to-idle a bit bloated anyway? Or has that been fixed. I know there was some issues with idle_balance() which can add latency to wakeups. idle_balance() is also in the to-idle path. Note, that this is a sched feature which would be a nop (jump_label) when disabled. And I'm sure it could also be optimized to be a static inline as well when it is enabled. I'm not saying we need to go this approach, but I'm just saying that the to-idle issue is a bit of a red herring. -- Steve