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Date: Mon, 24 Nov 1997 21:14:21 +1100
From: Bruce Evans <bde@zeta.org.au>
Message-Id: <199711241014.VAA09419@godzilla.zeta.org.au>
To: fs@freebsd.org
Subject: ufs slowness
Sender: owner-freebsd-fs@freebsd.org
X-Loop: FreeBSD.org
Precedence: bulk

ffs (with a block size of 8K and a frag size of 1K) seems to be about
twice as slow as ext2fs (with a block size of 4K and a frag size of 4K)
for reading small files.  This seems to be due to ffs doing lots more
seeks.  E.g., for `tar cf /dev/null linux-2.1.63' where there are about
50MB of files in the directory, ffs takes about 40 seconds and ext2fs
takes about 20 seconds.  The extfs partition is on faster tracks but
is fuller.  Typical output from systat:

		ext2fs	ffs
	seeks	372	144
	xfers	372	145
	blks	2751	1395
	msps	0.5	4.1

This was on an IDE so `msps' may actually be right (though it may be broken
for dma mode).  All file systems were mounted async,noatime.  2.5MB/sec
exploits about half the disk bandwidth.

Bruce