From owner-cvs-src@FreeBSD.ORG Wed Jun 8 20:26:06 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 8E1D116A41C; Wed, 8 Jun 2005 20:26:06 +0000 (GMT) (envelope-from jeff@FreeBSD.org) Received: from repoman.freebsd.org (repoman.freebsd.org [216.136.204.115]) by mx1.FreeBSD.org (Postfix) with ESMTP id 6DF5A43D4C; Wed, 8 Jun 2005 20:26:06 +0000 (GMT) (envelope-from jeff@FreeBSD.org) Received: from repoman.freebsd.org (localhost [127.0.0.1]) by repoman.freebsd.org (8.13.1/8.13.1) with ESMTP id j58KQ6Ls052317; Wed, 8 Jun 2005 20:26:06 GMT (envelope-from jeff@repoman.freebsd.org) Received: (from jeff@localhost) by repoman.freebsd.org (8.13.1/8.13.1/Submit) id j58KQ6cT052316; Wed, 8 Jun 2005 20:26:06 GMT (envelope-from jeff) Message-Id: <200506082026.j58KQ6cT052316@repoman.freebsd.org> From: Jeff Roberson Date: Wed, 8 Jun 2005 20:26:06 +0000 (UTC) To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org X-FreeBSD-CVS-Branch: HEAD Cc: Subject: 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: Wed, 08 Jun 2005 20:26:06 -0000 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