Re: mpt Serious performance issues

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

On Fri, 26 Nov 2010, Stephan wrote:
> I already sent this to netbsd-users but didn´t get an answer. The
> Netbsd mpt driver in release 5.0.2 and 5.1 does perform extremely slow
> on LSI Logic 1030 RAID controllers. Some findings:
>
> Write speed:
>
> # dd if=/dev/zero of=myfile bs=4096 count=10000
> 10000+0 records in
> 10000+0 records out
> 40960000 bytes transferred in 12.762 secs (3209528 bytes/sec)
>
> Read speed after reboot:
>
> # dd if=myfile of=/dev/null
> 80000+0 records in
> 80000+0 records out
> 40960000 bytes transferred in 6.929 secs (5911386 bytes/sec)
[snip]
> Obviously, there is no write cache. FreeBSDs mpt driver is performing
> much faster (over 60MB/s). What could be wrong here?

I'm surprised by the read speed, but even under Windows I see terrible 
write performance with the 1030. Copying a large file so overloads the 
machine that the pointer keeps jamming for a few seconds.