[Cluster-devel] [GFS2 PATCH] GFS2: Don't brelse rgrp buffer_heads every allocation

[Bob Peterson <rpeterso@redhat.com>]

----- Original Message -----
> I'm assuming that these figures are bandwidth rather than times, since
> that appears to show that the patch makes quite a large difference.
> However the reclen is rather small. In the 32 bytes case, thats 128
> writes for each new block thats being allocated, unless of course that
> is 32k?
> 
> Steve.

Hi,

To do this test, I'm executing this command:
numactl --cpunodebind=0 --membind=0 /home/bob/iozone/iozone3_429/src/current/iozone -az -f /mnt/gfs2/iozone-gfs2 -n 2048m -g 2048m -y 32k -q 1m -e -i 0 -+n &> /home/bob/iozone.out

According to iozone -h, specifying -y this way is 32K, not 32 bytes.
The -q is maximum write size, in KB, so -q 1m is 1MB writes.
The -g is maximum file size, in KB, so -g 2048 is a 2MB file.

So the test varies the writes from 32K to 1MB, adjusting the number
of writes to get the file to 2MB.

Regards,

Bob Peterson
Red Hat File Systems