Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19

Martin J. Bligh
2005-11-04T16:13:28Z

> So I suspect Martin's 25% is a lot more accurate on modern hardware (which
> means x86, possibly Power. Nothing else much matters).

It was PPC64, if that helps.

>> If your and other kernel developer's (<<0.01% of the universe) kernel
>> builds slow down by 5% and my and other people's simulations (perhaps
>> 0.01% of the universe) speed up by a factor up to 3 or 4, who wins?
>
> First off, you won't speed up by a factor of three or four. Not even
> _close_.

Well, I think it depends on the workload a lot. However fast your TLB is,
if we move from "every cacheline read requires is a TLB miss" to "every
cacheline read is a TLB hit" that can be a huge performance knee however
fast your TLB is. Depends heavily on the locality of reference and size
of data set of the application, I suspect.

M.