From owner-cvs-sys Wed Aug 9 07:55:54 1995 Return-Path: cvs-sys-owner Received: (from majordom@localhost) by freefall.FreeBSD.org (8.6.11/8.6.6) id HAA16188 for cvs-sys-outgoing; Wed, 9 Aug 1995 07:55:54 -0700 Received: from Sysiphos (Sysiphos.MI.Uni-Koeln.DE [134.95.212.10]) by freefall.FreeBSD.org (8.6.11/8.6.6) with SMTP id HAA16179 ; Wed, 9 Aug 1995 07:55:34 -0700 Received: by Sysiphos id AA09425 (5.67b/IDA-1.5); Wed, 9 Aug 1995 14:10:48 +0200 Message-Id: <199508091210.AA09425@Sysiphos> From: esser@zpr.uni-koeln.de (Stefan Esser) Date: Wed, 9 Aug 1995 14:10:47 +0200 In-Reply-To: David Greenman "cvs commit: src/sys/ufs/ffs ffs_inode.c" (Aug 3, 22:49) X-Mailer: Mail User's Shell (7.2.6 alpha(2) 7/9/95) To: David Greenman Subject: Re: cvs commit: src/sys/ufs/ffs ffs_inode.c Cc: CVS-commiters@freefall.freebsd.org, cvs-sys@freefall.freebsd.org Sender: cvs-sys-owner@freebsd.org Precedence: bulk On Aug 3, 22:49, David Greenman wrote: } Subject: cvs commit: src/sys/ufs/ffs ffs_inode.c } davidg 95/08/03 22:49:18 } } Modified: sys/ufs/ffs ffs_inode.c } Log: } Use the correct flags (IO_SYNC -> B_SYNC) when deciding to do a sync or } async write in the section that changes the filesize. The bug resulted } in the updates always being async. What performance improvement is to expect from that patch ? Does it only make a difference if a file is modified, not if it is created or deleted ? I did some tests, creating and deleting 1000 files from a small shell script: #!/bin/sh for i in 0 1 2 3 4 5 6 7 8 9 do mkdir $i for j in 0 1 2 3 4 5 6 7 8 9 do mkdir $i/$j for k in 0 1 2 3 4 5 6 7 8 9 do echo "file $i$j$k" > $i/$j/$k done done done I found that the "-async" option made no difference at all ! Using "simple" tags instead of "ordered" tags for writes made the drive reorder file and meta data updates, resulting in 30% higher file creation rate ... f1000.sh ======== tags simple ASYNC SYNC --------------------------------------------- 4 n 37.59 36.65 16 n 36.89 31.75 16 y 28.55 28.58 rm -rf * ======== tags simple ASYNC SYNC --------------------------------------------- 4 n 24.30 23.34 16 n 23.87 21.53 16 y 22.56 22.82 I would have expected the ASYNC mount to make much more of a diference ... Regards, STefan -- Stefan Esser Internet: Zentrum fuer Paralleles Rechnen Tel: +49 221 4706021 Universitaet zu Koeln FAX: +49 221 4705160 Weyertal 80 50931 Koeln