Page fault, GEOM problem??

[Johan Ström]

On 19 nov 2005, at 02.35, Pawel Jakub Dawidek wrote:

> On Sat, Nov 19, 2005 at 01:55:57AM +0100, Johan Ström wrote:
<snip>
> +> I just noticed another thing... My disk performance... sucks! :P
> +>
> +> Some examples (from an otherwise unloaded system):
> +>
> +> root at elfi:/home/johan$ time dd if=/dev/zero of=bigfile.zero  
> bs=1024 count=1000000
> +> 1000000+0 records in
> +> 1000000+0 records out
> +> 1024000000 bytes transferred in 77.014797 secs (13296146 bytes/sec)
>
> You won't get more with such small block size. Try bs=128k.

Hi
Can't say that a bigger blocksize did much better..

root at elfi:/home/johan$ time dd if=/dev/zero of=bigfile.zero bs=128k  
count=10000
10000+0 records in
10000+0 records out
1310720000 bytes transferred in 98.519181 secs (13304211 bytes/sec)

root at elfi:/home/johan$ time dd if=/dev/zero of=bigfile.zero bs=512k  
count=10000
^C3587+0 records in
3587+0 records out
1880621056 bytes transferred in 145.049578 secs (12965367 bytes/sec)

root at elfi:/home/johan$ time dd if=/dev/zero of=bigfile.zero bs=50k  
count=10000
10000+0 records in
10000+0 records out
512000000 bytes transferred in 38.536217 secs (13286203 bytes/sec)

All this time, iostats MB/s column wouldnt go over 0.24MB/s...

Back on GENERIC:

root at elfi:/home/johan$ time dd if=/dev/zero of=bigfile.zero bs=128k  
count=10000
10000+0 records in
10000+0 records out
1310720000 bytes transferred in 99.497358 secs (13173415 bytes/sec)

root at elfi:/home/johan$ time dd if=/dev/zero of=bigfile.zero bs=512k  
count=1000
1000+0 records in
1000+0 records out
524288000 bytes transferred in 39.019239 secs (13436654 bytes/sec)

Still slow.. However, iostat goes up as high as 5.64MB/s on each disk  
in the mirror.



>
> -- 
> Pawel Jakub Dawidek                       http://www.wheel.pl
> pjd at FreeBSD.org                           http://www.FreeBSD.org
> FreeBSD committer                         Am I Evil? Yes, I Am!