From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 11 Mar 2006 15:41:13 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH/RFC] AutoPage Migration - V0.1 - 0/8 Overview Message-Id: <20060311154113.c4358e40.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1142019195.5204.12.camel@localhost.localdomain> References: <1142019195.5204.12.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: lee.schermerhorn@hp.com Cc: linux-mm@kvack.org List-ID: Hi, a few comments. On Fri, 10 Mar 2006 14:33:14 -0500 Lee Schermerhorn wrote: > Furthermore, to prevent thrashing, a second > sysctl, sched_migrate_interval, has been implemented. The load balancer > will not move a task to a different node if it has move to a new node > in the last sched_migrate_interval seconds. [User interface is in > seconds; internally it's in HZ.] The idea is to give the task time to > ammortize the cost of the migration by giving it time to benefit from > local references to the page. I think this HZ should be automatically estimated by the kernel. not by user. > Kernel builds [after make mrproper+make defconfig] > on 2.6.16-rc5-git11 on 16-cpu/4 node/32GB HP rx8620 [ia64]. > Times taken after a warm-up run. > Entire kernel source likely held in page cache. > This amplifies the effect of the patches because I > can't hide behind disk IO time. It looks you added check_internode_migration() in migrate_task(). migrate_task() is called by sched_migrate_task(). And....sched_migrate_task() is called by sched_exec(). (a process can be migrated when exec().) In this case, migrate_task_memory() just wastes time..., I think. BTW, what happens against shared pages ? -- Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org