Re: [BENCHMARK] max bomb segment tuning with read latency 2 patch in contest

GrandMasterLee
2002-12-07T06:07:27Z

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.

Command tag queue? As in the compile time option? Or do you mean queue
depth?(or are they the same)

> But as you're interested in `desktop responsiveness' you should be
> mostly testing against IDE disks. Their behavour tends to be quite
> different.
>
> If you can turn on write caching on the SCSI disks that would change
> the picture too.

Just for clarity, What about for something like FC attached storage
Where the controllers enforce cache policies on a "per volume" basis?
Would that == the same thing?

--The GrandMaster