Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753300AbaDXU1M (ORCPT ); Thu, 24 Apr 2014 16:27:12 -0400 Received: from forward17.mail.yandex.net ([95.108.253.142]:48128 "EHLO forward17.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752412AbaDXU1K (ORCPT ); Thu, 24 Apr 2014 16:27:10 -0400 X-Greylist: delayed 609 seconds by postgrey-1.27 at vger.kernel.org; Thu, 24 Apr 2014 16:27:10 EDT From: Kirill Tkhai To: Peter Zijlstra , Roman Gushchin Cc: LKML , "mingo@redhat.com" , Artyom Tarasenko In-Reply-To: <20140424185858.GB26782@laptop.programming.kicks-ass.net> References: <36851398363372@webcorp2g.yandex-team.ru> <20140424185858.GB26782@laptop.programming.kicks-ass.net> Subject: Re: Real-time scheduling policies and hyper-threading MIME-Version: 1.0 Message-Id: <968281398370612@web21g.yandex.ru> X-Mailer: Yamail [ http://yandex.ru ] 5.0 Date: Fri, 25 Apr 2014 00:16:52 +0400 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=koi8-r Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 24.04.2014, 22:59, "Peter Zijlstra" : [snip] >> ?Does anyone use rt-scheduler for runtime-like cpu-bound tasks? > > So in general cpu bound tasks in the RT classes (FIFO/RR/DEADLINE) are > bad and can make the system go funny. > > For general system health it is important that various system tasks > (kthreads usually) can run. Many of these kthreads run at !rt prios, and > by having cpu bound tasks in rt prios they don't get to run. One more word to this. I had such expirience on 2.6.33 kernel with RT patch and weak hardware (sparc32). Networking was actively used and application did not use any IO operations. User needs to set all RT priorities by himself. It's necessary to set RT priorities at least for softirqs and rcus. RT bandwidth must be switched off. The most giving optimization, which I receive, was after rejection from NAPI for network adapters and splitting interrupt handler on hard and threadparts. In this case game with binding for everything strongly improves the picture for single problem. Kirill -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/