[Cluster-devel] [GFS2 PATCH 0/5] GFS2: Bitmap search optimizations

[Bob Peterson <rpeterso@redhat.com>]

This set of 5 patches increases the speed of GFS2's bitmap search
algorithms. To test the performance, I added instrumentation to
function gfs2_inplace_reserve to report the amount of time spent
there. With the "stock" gfs2, I got 64586490 microseconds while
running postmark with 100000 transactions and 100000 files.
With the patched gfs2, I got 49441435, which is nearly 24% faster.
Without the 5 GFS2 patches, postmark gave this result:
852.13 megabytes written (970.61 kilobytes per second)
With the 5 patches GFS2, I got:
852.13 megabytes written (979.32 kilobytes per second)
So overall, postmark performance was only 1% faster.
Using straight dd copying 1MB files, I got 10% faster. Obviously
mileage will vary: my hardware isn't the fastest.

The patches are as follows:

[PATCH 1/5] GFS2: optimize rbm_from_block wrt bi_start
[PATCH 2/5] GFS2: introduce bi_blocks for optimization
[PATCH 3/5] GFS2: Introduce rbm field bii
[PATCH 4/5] GFS2: new function gfs2_rbm_incr
[PATCH 5/5] GFS2: Do not reset flags on active reservations

Regards,

Bob Peterson
Red Hat File Systems