Re: Re: poor domU VBD performance.

[Nicholas Lee <emptysands@gmail.com>]

Some simple non-scientific additions to the performance numbers. IBM
x335/MPT SCSI.

Previously on 2.0.5/Testing on 2.6.10:

[nic@stateless:~/sys/xen] sudo hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   2884 MB in  2.00 seconds = 1442.00 MB/sec
 Timing buffered disk reads:  100 MB in  3.05 seconds =  32.79 MB/sec

Not completely happy with the buffered read figure of 34Mb.  I'm
putting together a new x205 server with Xen later today. I'll try do
some native vs Xen testing while I'm at it.

dom0:
[nic@stateless:~/tmp] time sudo  cp db-svn.tgz db-svn-bak.tgz

real    0m13.058s
user    0m0.030s
sys     0m0.530s

domU:
[nic@base:/export/bak] time sudo  cp db-svn.tgz db-svn-bak.tgz

real    0m23.574s
user    0m0.010s
sys     0m0.060s


[nic@stateless:~/tmp] ls -l db-svn.tgz
-rw-r--r--  1 nic nic 188247603 2005-04-04 21:06 db-svn.tgz

With todays 2.0.6/Testing on 2.6.11.6:

[nic@stateless:~] sudo hdparm -tT /dev/sda

/dev/sda:
 Timing cached reads:   2748 MB in  2.00 seconds = 1374.00 MB/sec
 Timing buffered disk reads:  102 MB in  3.00 seconds =  34.00 MB/sec

[nic@stateless:~/tmp] time sudo  cp db-svn.tgz db-svn-bak.tgz

real    0m10.468s
user    0m0.010s
sys     0m0.070s


[nic@base:/export/bak] time sudo  cp db-svn.tgz db-svn-bak.tgz

real    0m11.243s
user    0m0.000s
sys     0m0.040s

Both filesystems based on XFS/LVM2. These numbers are based on one-run
right after boot, with in the domU case just one domU running.

So definite improvement.

Nicholas