On Fri, 2002-12-06 at 23:55, Andrew Morton wrote:
[...]
> If the SMP machine is using scsi then that tends to make the elevator
> changes less effective. Because the disk sort-of has its own internal
> elevator which in my testing on a Fujitsu disk has the same ill-advised
> design as the kernel's elevator: it treats reads and writes in a similar
> manner.
>
> Setting the tag depth to zero helps heaps.
>
> But as you're interested in `desktop responsiveness' you should be
> mostly testing against IDE disks. Their behavour tends to be quite
> different.
One interesting thing about my current setup, with all scsi or FC disks,
is that bomb never displays > 0.
Example:
elvtune /dev/sdn yields:
/dev/sdn elevator ID 17
read_latency: 8192
write_latency: 16384
max_bomb_segments: 0
elvtune -b 6 /dev/sdn yields:
/dev/sdn elevator ID 17
read_latency: 8192
write_latency: 16384
max_bomb_segments: 0
Is it because I just do volume management at the hardware level and use
whole disks? Or is that something else?
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This archive was generated by hypermail 2b29 : Sat Dec 07 2002 - 22:00:29 EST