On Wed, May 1, 2013 at 4:11 PM, Or Gerlitz <[email protected]> wrote: > This was done over kernel 3.5.x, I will re-run tomorrow with latest > upstream and send the top perf hits for both cases, but does this > rings some bells? basically it makes sense for some extra latency, but > I didn't expect the IOPS and BW drop to be so notable. Is it possible > that at these rates the IOMMU is so much trashed that it can't keep > the perf we have without it being on?
Using the IOMMU makes the dma mapping API *much* more expensive. Look at the recent thread about NFS/RDMA performance for another instance of this. - R. _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
