On Mon, May 15, 2023 at 11:15:56AM +0200, Niklas Schnelle wrote: > In the s390 IOMMU driver a large fixed queue size and timeout is then > set together with single queue mode bringing its performance on s390 > paged memory guests on par with the previous s390 specific DMA API > implementation. Hmm, the right flush-queue size and timeout settings are more a function of the endpoint device and device driver than of the iommu driver, no? I think something like this could also help solving the recently reported scalability problems in the fq-code, if done right. Regards, Joerg