[emmericp]

Interesting, did you use huge pages?

I think ~100k to 200k TSO "packets" per second should be doable with the IOMMU. But I guess it depends where the data is coming from. Could be one of the odd cases where copying data is faster than doing zero-copy, e.g., just copy everything into the same small set of small-ish buffers to keep the number of pages that need to be present in the IOMMU small?