From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933064AbcA3RxL (ORCPT ); Sat, 30 Jan 2016 12:53:11 -0500 Received: from mail-wm0-f65.google.com ([74.125.82.65]:35903 "EHLO mail-wm0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932586AbcA3RxJ (ORCPT ); Sat, 30 Jan 2016 12:53:09 -0500 Message-ID: <1454176385.3797.23.camel@gmail.com> Subject: Re: [PATCH 2/2] sched,time: call __acct_update_integrals once a jiffy From: Mike Galbraith To: Frederic Weisbecker , Rik van Riel Cc: linux-kernel@vger.kernel.org, tglx@linutronix.de, mingo@kernel.org, peterz@infradead.org, luto@amacapital.net, Clark Williams Date: Sat, 30 Jan 2016 18:53:05 +0100 In-Reply-To: <20160130142037.GA32581@lerouge> References: <1454106180-20918-1-git-send-email-riel@redhat.com> <1454106180-20918-3-git-send-email-riel@redhat.com> <56ABEB10.5060307@redhat.com> <20160130142037.GA32581@lerouge> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.16.5 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2016-01-30 at 15:20 +0100, Frederic Weisbecker wrote: > On Fri, Jan 29, 2016 at 05:43:28PM -0500, Rik van Riel wrote: > > Run times for the microbenchmark: > > > > 4.4 3.8 seconds > > 4.5-rc1 3.7 seconds > > 4.5-rc1 + first patch 3.3 seconds > > 4.5-rc1 + both patches 2.3 seconds > > Very nice improvement! Tasty indeed. When nohz_full CPUs are not isolated, ie are being used as generic CPUs, get_nohz_timer_target() is a problem with things like tbench. tbench 8 with Rik's patches applied: nohz_full=empty Throughput 3204.69 MB/sec 1.000 nohz_full=1-3,5-7 Throughput 1354.99 MB/sec .422 1.000 nohz_full=1-3,5-7 + club below Throughput 2762.22 MB/sec .861 2.038 With Rik's patches and a club, tbench becomes nearly acceptable. --- include/linux/tick.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/include/linux/tick.h +++ b/include/linux/tick.h @@ -184,7 +184,7 @@ static inline const struct cpumask *hous static inline bool is_housekeeping_cpu(int cpu) { #ifdef CONFIG_NO_HZ_FULL - if (tick_nohz_full_enabled()) + if (tick_nohz_full_enabled() && runqueue_is_isolated(cpu)) return cpumask_test_cpu(cpu, housekeeping_mask); #endif return true;