Date: Wed, 9 Aug 1995 14:10:47 +0200 From: esser@zpr.uni-koeln.de (Stefan Esser) To: David Greenman <davidg@freefall.freebsd.org> Cc: CVS-commiters@freefall.freebsd.org, cvs-sys@freefall.freebsd.org Subject: Re: cvs commit: src/sys/ufs/ffs ffs_inode.c Message-ID: <199508091210.AA09425@Sysiphos> In-Reply-To: David Greenman <davidg@freefall.cdrom.com> "cvs commit: src/sys/ufs/ffs ffs_inode.c" (Aug 3, 22:49)
next in thread | previous in thread | raw e-mail | index | archive | help
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: <se@ZPR.Uni-Koeln.DE>
Zentrum fuer Paralleles Rechnen Tel: +49 221 4706021
Universitaet zu Koeln FAX: +49 221 4705160
Weyertal 80
50931 Koeln
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199508091210.AA09425>