Re: Resets on sil3124 & sil3726 PMP

[Petr Vandrovec <vandrove@vc.cvut.cz>]

Robin H. Johnson wrote:
> On Wed, Sep 05, 2007 at 05:08:00AM -0700, Petr Vandrovec wrote:
>>> 3124-2 (norco 4618):
>>> NCQ:
>>> 1TB alone:   82.30, 82.43
>>> 1TB+1TB:     68.36+68.25
>>> noNCQ:
>>> 1TB alone:   82.39, 82.29
>>> 1TB+1TB:     70.33+70.32, 69.47+70.01
>>> Unfortunately that enclosure has only two slots used.  I'll try to not 
>>> forget bring two more disks tomorrow to get it fully populated.
>>  In case you are still follwing this thread, 3124-2 with 4 1TB drives 
>>  delivers 58.5MBps for each drive with NCQ enabled, and 60MBps with NCQ 
>>  disabled - total 235-240MBps read speed.  I would like to see 320MBps, but 
>>  apparently today is not my lucky day...
> Just to confirm, how were you testing the multiple drive combination?

Concurrent hdparm -t, like

hdparm -t /dev/sdd & hdparm -t /dev/sde & hdparm -t /dev/sdf & hdparm -t 
/dev/sdg & sleep 20

(and from hdparm output & visually confirmed that all activity LEDs go 
on & off simultaneously)

So NCQ should not be able to show any (definitely not huge) benefits, 
but there should not be any reason to not get 4x 1 drive speed as long 
as neither PMP link nor PCI-X limits are hit.
								Petr