RESOLVED : Low perf with smp on DELL server

[Mark Kirkwood]

Eric wrote:
> Hi Mark,
> 
> I do a lot new test, re-install all system   and arrive now to this :
> Test without SMP : 29 sec
> Test with SMP      : 37 sec
> Wich is very far from the 62 sec we have before with SMP and seems to be 
> "normal" for most people saying SMP and 4.11 are not so friend they 
> seems to be. Ok for you?
> 
> It seems that problem before, came from perc4 controller configuration. 
> It seems that if you change configuration on fly you don't have the same 
> result ;=(  as if you re-create the logical drive with good param and 
> put same param onfly .
> Good configuration is for me disable any cache  :
> On creation and on configuration :  Write Policy --> Writethru
>                                                   Read Policy --> 
> non-adaptive
> Don't know why difference  was more important with SMP but it seems to 
> be now ok.
> 
> As there is still few difference with SMP, I  now do same test but 
> launching 1, 2, or 3 test in same time to see if it's usefulle for me to 
> have SMP kernel. Result is really near but I doubt that it's not 
> hardrive that slow down all system.
> 
> Do you know a way to know the hard drive utilisation as with top? 
> (iostat always return 0)
> Do you know a way to do high ramdrive? (I try with mount_mfs but it 
> always limit me to 400 Mo)
>

Well done - so you nailed it down to the controller! (chuckles - you 
might find 6.0 works better than 4.11 with SMP *now*)....

With respect to the perc4 not showing up on iostat, could be that 4.11's 
support for this card is rudimentary - I would suggest starting a new 
thread asking about this!

Cheers

Mark