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SubjectRe: [RFC] block layer support for DMA IOMMU bypass mode II
On Tue, 2003-07-29 at 23:42, Grant Grundler wrote:
> On Mon, Jul 28, 2003 at 01:15:13PM +0200, Andi Kleen wrote:
> > Run it with 100-500 users (reaim -f workfile... -s 100 -e 500 -i 100)
> jejb was wondering if 4k pages would cause different behaviors becuase
> of file system vs page size (4k vs 16k). ia64 uses 16k by default.
> I've rebuilt the kernel with 4k page size and VMERGE != 0.
> The substantially worse performance feels like a rat hole because
> of 4x pressure on CPU TLB.

OK, I admit it, it was a rat hole. Provided reaim uses large files, we
should only get block<->page fragmentation at the edges, and obviously,
reaim has to use large files otherwise it's not testing the virtual
merging properly...


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