From owner-cvs-src@FreeBSD.ORG Thu Jun 9 13:54:39 2005 Return-Path: X-Original-To: cvs-src@FreeBSD.org Delivered-To: cvs-src@FreeBSD.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 2EEF916A41C; Thu, 9 Jun 2005 13:54:39 +0000 (GMT) (envelope-from bright@elvis.mu.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.FreeBSD.org (Postfix) with ESMTP id 08F0843D49; Thu, 9 Jun 2005 13:54:38 +0000 (GMT) (envelope-from bright@elvis.mu.org) Received: by elvis.mu.org (Postfix, from userid 1192) id C52205CA47; Thu, 9 Jun 2005 06:54:38 -0700 (PDT) Date: Thu, 9 Jun 2005 06:54:38 -0700 From: Alfred Perlstein To: Jeff Roberson Message-ID: <20050609135438.GS17867@elvis.mu.org> References: <200506082026.j58KQ6cT052316@repoman.freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200506082026.j58KQ6cT052316@repoman.freebsd.org> User-Agent: Mutt/1.4.2.1i Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/kern vfs_bio.c X-BeenThere: cvs-src@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the src tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Jun 2005 13:54:39 -0000 MFC? :D * Jeff Roberson [050608 13:26] wrote: > jeff 2005-06-08 20:26:06 UTC > > FreeBSD src repository > > Modified files: > sys/kern vfs_bio.c > Log: > - Under heavy IO load the buf daemon can run for many hundereds of > milliseconds due to what is essentially n^2 algorithmic complexity. This > change makes the algorithm N*2 instead. This heavy processing manifested > itself as skipping in audio and video playback due to the long scheduling > latencies and contention on giant by pcm. > - flushbufqueues() is now responsible for flushing multiple buffers > rather than one at a time. This allows us to save our progress in the > list by using a sentinal. We must do the numdirtywakeup() and > waitrunningbufspace() here now rather than in buf_daemon(). > - Also add a uio_yield() after we have processed the list once for bufs > without deps and again for bufs with deps. This is to release Giant > and allow any other giant locked code to proceed. > > Tested by: Many users on current@ > Revealed by: schedgraph traces sent by Emil Mikulic & Anthony Ginepro > > Revision Changes Path > 1.487 +28 -6 src/sys/kern/vfs_bio.c -- - Alfred Perlstein - email: bright@mu.org cell: 408-480-4684