Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754203AbYHTRXn (ORCPT ); Wed, 20 Aug 2008 13:23:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751269AbYHTRXf (ORCPT ); Wed, 20 Aug 2008 13:23:35 -0400 Received: from viefep32-int.chello.at ([62.179.121.50]:45991 "EHLO viefep32-int.chello.at" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750948AbYHTRXe (ORCPT ); Wed, 20 Aug 2008 13:23:34 -0400 Subject: Re: VolanoMark regression with 2.6.27-rc1 From: Peter Zijlstra To: Ray Lee Cc: Nick Piggin , adobriyan@gmail.com, Ingo Molnar , "Zhang, Yanmin" , Dhaval Giani , LKML , Srivatsa Vaddagiri , Aneesh Kumar KV , Balbir Singh , Chris Friesen In-Reply-To: <2c0942db0808200929r640b3a1cj33efc56cfd6db9b3@mail.gmail.com> References: <1912217169.25608.228.camel@ymzhang> <20080820143209.GA32156@x200.localdomain> <1219242796.8651.54.camel@twins> <200808210110.37204.nickpiggin@yahoo.com.au> <2c0942db0808200929r640b3a1cj33efc56cfd6db9b3@mail.gmail.com> Content-Type: text/plain Date: Wed, 20 Aug 2008 19:21:41 +0200 Message-Id: <1219252901.8651.63.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.3.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2423 Lines: 81 Ok, so one last time (I hope!).. Everybody happy with this? --- Subject: sched: load-balance bias fixes From: Peter Zijlstra Date: Wed Aug 20 15:28:51 CEST 2008 Yanmin spotted a regression with my patch that introduces LB_BIAS: commit 93b75217df39e6d75889cc6f8050343286aff4a5 Author: Peter Zijlstra Date: Fri Jun 27 13:41:33 2008 +0200 And I just spotted the brainfart - I should have replaced min/max with avg instead of removing it completely. [ray-lk@madrabbit.org: better avg implementation] Signed-off-by: Peter Zijlstra --- include/linux/kernel.h | 6 ++++++ kernel/sched.c | 10 ++++++++-- 2 files changed, 14 insertions(+), 2 deletions(-) Index: linux-2.6/kernel/sched.c =================================================================== --- linux-2.6.orig/kernel/sched.c +++ linux-2.6/kernel/sched.c @@ -2008,9 +2008,12 @@ static unsigned long source_load(int cpu struct rq *rq = cpu_rq(cpu); unsigned long total = weighted_cpuload(cpu); - if (type == 0 || !sched_feat(LB_BIAS)) + if (type == 0) return total; + if (!sched_feat(LB_BIAS)) + return avg(rq->cpu_load[type-1], total); + return min(rq->cpu_load[type-1], total); } @@ -2023,9 +2026,12 @@ static unsigned long target_load(int cpu struct rq *rq = cpu_rq(cpu); unsigned long total = weighted_cpuload(cpu); - if (type == 0 || !sched_feat(LB_BIAS)) + if (type == 0) return total; + if (!sched_feat(LB_BIAS)) + return avg(rq->cpu_load[type-1], total); + return max(rq->cpu_load[type-1], total); } Index: linux-2.6/include/linux/kernel.h =================================================================== --- linux-2.6.orig/include/linux/kernel.h +++ linux-2.6/include/linux/kernel.h @@ -367,6 +367,12 @@ static inline char *pack_hex_byte(char * (void) (&_max1 == &_max2); \ _max1 > _max2 ? _max1 : _max2; }) +#define avg(x, y) ({ \ + typeof(x) _avg1 = (x); \ + typeof(y) _avg2 = (y); \ + (void) (&_avg1 == &_avg2); \ + _avg1 + (_avg2 - _avg1)/2; }) + /** * clamp - return a value clamped to a given range with strict typechecking * @val: current value -- 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/