Very low disk performance on 5.x (some tweaking and more results)

[Steven Hartland]

Did you also try the sys/param.h change that helped here.
Also when testing on FS I found bs=1024k to degrade performance
try with 64k.
Is this a raid volume? If so on my setup anything other that a 16k stripe
and performance went out the window.

For the 'time' its easier to understand if u use:
/usr/bin/time -h

Last but not least. I found some very strange behaviour late last night.
If I created the raid set but didnt power down after doing so the
results where a lot lower than when I did. Dont ask me why I have
no idea, only noticed as I retested a result after I installed a new
fan in the machine and was totally a los

My initial starting results where:
Write: 140Mb/s
Read: 49Mb/s

My current values are:
Write: 140Mb/s
Read: 195Mb/s

Changes made:
1. 16k RAID5 stripe not 64k ( default )
2. vfs.read_max=16
3. MAXPHYS = 256 ( was 128 )
4. newfs /dev/da0 ( was a basic install with multi partitions )

I'm currently seeing some VERY strange behaviour which could
be the RAID controller negotiating different PCI-X speeds.

Anyone know how to check the state of a PCI-X card?

Power up, login:
dd if=/dev/da0 of=/dev/null bs=64k count=100000
100000+0 records in
100000+0 records out
6553600000 bytes transferred in 42.997295 secs (152418891 bytes/sec)
mount /dev/da0 /mnt
dd if=/mnt/testfile of=/dev/null bs=64k count=100000
100000+0 records in
100000+0 records out
6553600000 bytes transferred in 48.757091 secs (134413270 bytes/sec)
shutdown -p now

Power up, login:
dd if=/dev/da0 of=/dev/null bs=64k count=100000
100000+0 records in
100000+0 records out
6553600000 bytes transferred in 28.365671 secs (231039838 bytes/sec)
mount /dev/da0 /mnt
dd if=/mnt/testfile of=/dev/null bs=64k count=100000
100000+0 records in
100000+0 records out
6553600000 bytes transferred in 32.012170 secs (204722143 bytes/sec)

    Steve
----- Original Message ----- 
From: "Mike Tancsa" <mike at sentex.net>
> OK, some further tests, trying to control for this.  I am not sure what 
> values to actually fiddle with via bsdlable as this is the entire disk so I 
> will just vary mounting da0 vs da0s1d.   I also cvsup'd to current as of 
> yesterday (FreeBSD nfs.sentex.ca 6.0-CURRENT FreeBSD 6.0-CURRENT #0: Mon 
> May  2 15:03:53 EDT 2005).  I will also try with Scott's changes to the 
> driver which went in after.
> 
> Also, the newfs params does seem to make a very big difference and 
> vfs.read_max as well.
....


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