From: Frank Mayhar Date: Wed, 7 Jan 2009 05:06:22 +0000 (-0500) Subject: ext4: Allow ext4 to run without a journal X-Git-Tag: v2.6.29-rc1~40^2~40 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0390131ba84fd3f726f9e24fc4553828125700bb;p=pandora-kernel.git ext4: Allow ext4 to run without a journal A few weeks ago I posted a patch for discussion that allowed ext4 to run without a journal. Since that time I've integrated the excellent comments from Andreas and fixed several serious bugs. We're currently running with this patch and generating some performance numbers against both ext2 (with backported reservations code) and ext4 with and without a journal. It just so happens that running without a journal is slightly faster for most everything. We did iozone -T -t 4 s 2g -r 256k -T -I -i0 -i1 -i2 which creates 4 threads, each of which create and do reads and writes on a 2G file, with a buffer size of 256K, using O_DIRECT for all file opens to bypass the page cache. Results: ext2 ext4, default ext4, no journal initial writes 13.0 MB/s 15.4 MB/s 15.7 MB/s rewrites 13.1 MB/s 15.6 MB/s 15.9 MB/s reads 15.2 MB/s 16.9 MB/s 17.2 MB/s re-reads 15.3 MB/s 16.9 MB/s 17.2 MB/s random readers 5.6 MB/s 5.6 MB/s 5.7 MB/s random writers 5.1 MB/s 5.3 MB/s 5.4 MB/s So it seems that, so far, this was a useful exercise. Signed-off-by: Frank Mayhar Signed-off-by: "Theodore Ts'o" --- Reading git-diff-tree failed