Messages in this thread | | | Date | Wed, 9 Jul 2003 20:55:15 +0200 | From | Andi Kleen <> | Subject | Re: [RFC] block layer support for DMA IOMMU bypass mode II |
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On Tue, 08 Jul 2003 15:23:14 -0700 (PDT) "David S. Miller" <davem@redhat.com> wrote:
> From: Grant Grundler <grundler@parisc-linux.org> > Date: Tue, 8 Jul 2003 16:25:45 -0600 > > On Tue, Jul 08, 2003 at 03:04:33PM -0700, David S. Miller wrote: > > Do you know a common PCI block device that would benefit from this > > (performs significantly better with short sg lists)? It would be > > interesting to test. > > > > %10 to %15 on sym53c8xx devices found on sparc64 boxes. > > Which workload? > > dbench type stuff, but that's a hard thing to test these days with > the block I/O schedulers changing so much. Try to keep that part > constant in the with/vs/without VIO_VMERGE!=0 testing :)
With MPT-Fusion and reaim "new dbase" load it seems to be slightly faster with forced IOMMU merging on Opteron, but the differences are quite small (~4%) and could be measurement errors.
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