From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753990AbdHRB0B (ORCPT ); Thu, 17 Aug 2017 21:26:01 -0400 Received: from LGEAMRELO11.lge.com ([156.147.23.51]:60923 "EHLO lgeamrelo11.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753482AbdHRBZ7 (ORCPT ); Thu, 17 Aug 2017 21:25:59 -0400 X-Original-SENDERIP: 156.147.1.125 X-Original-MAILFROM: byungchul.park@lge.com X-Original-SENDERIP: 10.177.222.33 X-Original-MAILFROM: byungchul.park@lge.com Date: Fri, 18 Aug 2017 10:25:55 +0900 From: Byungchul Park To: peterz@infradead.org, mingo@kernel.org Cc: linux-kernel@vger.kernel.org, juri.lelli@gmail.com, rostedt@goodmis.org, kernel-team@lge.com Subject: Re: [PATCH v6 0/2] Make find_later_rq() choose a closer cpu in topology Message-ID: <20170818012555.GY20323@X58A-UD3R> References: <1502077834-11137-1-git-send-email-byungchul.park@lge.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1502077834-11137-1-git-send-email-byungchul.park@lge.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 07, 2017 at 12:50:32PM +0900, Byungchul Park wrote: > When cpudl_find() returns any among free_cpus, the cpu might not be > closer than others, considering sched domain. For example: > > this_cpu: 15 > free_cpus: 0, 1,..., 14 (== later_mask) > best_cpu: 0 > > topology: > > 0 --+ > +--+ > 1 --+ | > +-- ... --+ > 2 --+ | | > +--+ | > 3 --+ | > > ... ... > > 12 --+ | > +--+ | > 13 --+ | | > +-- ... -+ > 14 --+ | > +--+ > 15 --+ > > In this case, it would be best to select 14 since it's a free cpu and > closest to 15(this_cpu). However, currently the code select 0(best_cpu) > even though that's just any among free_cpus. Fix it. Could you let me know your opinions about this? > Change from v5 > -. exclude two patches already picked up by peterz > (sched/deadline: Make find_later_rq() choose a closer cpu in topology) > (sched/deadline: Change return value of cpudl_find()) > -. apply what peterz fixed for 'prefer sibling', into deadline and rt > > Change from v4 > -. remove a patch that might cause huge lock contention > (by spin lock(&cpudl.lock) in a hot path of scheduler) > > Change from v3 > -. rename closest_cpu to best_cpu so that it align with rt > -. protect referring cpudl.elements with cpudl.lock > -. change return value of cpudl_find() to bool > > Change from v2 > -. add support for SD_PREFER_SIBLING > > Change from v1 > -. clean up the patch > > Byungchul Park (2): > sched/deadline: Add support for SD_PREFER_SIBLING on find_later_rq() > sched/rt: Add support for SD_PREFER_SIBLING on find_lowest_rq() > > kernel/sched/deadline.c | 46 +++++++++++++++++++++++++++++++++++++++++++--- > kernel/sched/rt.c | 47 ++++++++++++++++++++++++++++++++++++++++++++--- > 2 files changed, 87 insertions(+), 6 deletions(-) > > -- > 1.9.1