Re: Industry db benchmark result on recent 2.6 kernels

[Nick Piggin <nickpiggin@yahoo.com.au>]

Linus Torvalds wrote:
> 
> On Fri, 1 Apr 2005, Chen, Kenneth W wrote:
> 
>>Paul, you definitely want to check this out on your large numa box.  I booted
>>a kernel with this patch on a 32-way numa box and it took a long .... time
>>to produce the cost matrix.
> 
> 
> Is there anything fundamentally wrong with the notion of just initializing
> the cost matrix to something that isn't completely wrong at bootup, and
> just lettign user space fill it in?
> 

That's probably not a bad idea. You'd have to do things like
set RT scheduling for your user tasks, and not have any other
activity happening. So that effectively hangs your system for
a while anyway.

But if you run it once and dump the output to a config file...

Anyway we're faced with the immediate problem of crap performance
for 2.6.12 (for people with 1500 disks), so an in-kernel solution
might be better in the short term. I'll see if we can adapt Ingo's
thingy with something that is "good enough" and doesn't take years
to run on a 512 way.

Nick

-- 
SUSE Labs, Novell Inc.