Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932655AbaFQMJq (ORCPT ); Tue, 17 Jun 2014 08:09:46 -0400 Received: from casper.infradead.org ([85.118.1.10]:49349 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932070AbaFQMJp (ORCPT ); Tue, 17 Jun 2014 08:09:45 -0400 Date: Tue, 17 Jun 2014 14:09:38 +0200 From: Peter Zijlstra To: Tim Chen Cc: Ingo Molnar , Andi Kleen , Michel Lespinasse , Rik van Riel , Peter Hurley , Jason Low , Davidlohr Bueson , linux-kernel@vger.kernel.org Subject: Re: [PATCH] sched: Fast idling of CPU when system is partially loaded Message-ID: <20140617120938.GN3213@twins.programming.kicks-ass.net> References: <1402608359.2970.548.camel@schen9-DESK> <20140615161921.GL11371@laptop.programming.kicks-ass.net> <1402933807.2970.577.camel@schen9-DESK> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="S4drRqups3dkeHIl" Content-Disposition: inline In-Reply-To: <1402933807.2970.577.camel@schen9-DESK> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --S4drRqups3dkeHIl Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Jun 16, 2014 at 08:50:07AM -0700, Tim Chen wrote: > > The worry I have is that this update is 'slow'. We could have grown many > > tasks since the last update. >=20 > The update to turn on the indicator is immediate and triggered in > add_nr_running. So if there are more than one tasks on any cpu,=20 > we start load balancing again right away. It is only the=20 > clearing of the indicator in update_sd_lb_stats that takes time. > That does no harm as the cleared indicator is for the skipping of load > balance, which can be delayed. >=20 Oh right, shows me I shouldn't be reading patches on sunday or similarly daft times ;) --S4drRqups3dkeHIl Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJToDACAAoJEHZH4aRLwOS69+IP/0AW0439ziqhgHzyPin2mQ2+ vUDq6fPsQNvHuOvgIlPFUyV0X2NIJKLBXJd+NJ9qHPizo+u4bIRG76YLm5eYbsII dLVBb2yysyjM3kSsg13D51tFjj7LucUG32FY7AEP8Y1sz9jhtHJjZL7kYuknogWB RlzGMBCXqQLOe0L6Q+6NSImJpfBaBXyYgSbGB8z6ZxfWWP0IMAgG0h0Aqzpzk7ka grwtTBX+rXYdAumWNhJ88C4KjjbRAZ5lEbyHpwuLN72r4J1aUtkuFzS3jMTw3Wnn ydw+wtLFrWZDH9AT9OvnTIb5sC8FGW2kMOS3lKnZAb3jkbM18/FA6kDNKLZIzAii sNc5qCK1ihukIY2t5rb2aoW9EuyYtXprDQcxCYmAsFlvcMWl+DHooxLriBTaBSI6 LEeAHmM1P11OlFZnu0sR1UOzzDSctjvwKX4aAZ6PFKolZqnfT0DIFBEAbai3XKcT EEr64gilwS5uaCdYzpkoCbcR+ptv1mvEniG4eMoi9y1Jkq4jlmzr9oMMIKFHjc1l uxbzgfPeNdCJaLjKeQPwPQsA+CU/ts0vNoFR0//+4011GSlOV5wz8m1/uvaQh0M2 6ZC73rJvaxB/H7gYimjWTcKXkzc7Fwn2iLS9HAvMtlsD3pf/6GfKyKarTSVR0MK0 OWqy/DBm3j+7vFhYoUcO =8kmZ -----END PGP SIGNATURE----- --S4drRqups3dkeHIl-- -- 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/