[dpdk-dev] zerocopy between userspace vhost virqueue and vmdq eth nic queu

dpdk dpdk at foxmail.com
Sun Mar 2 03:55:37 CET 2014

From ver 1.6, dpdk support userspace vhost backend, which is very useful for high performance & low lagency soft vswitching.

But as I see the sample in git tree (dpdk.org/browse/dpdk/tree/examples/vhost/main.c), packets tx/rx between peth nic and virtio vnic queues are both copied once.

Since gust vm are created on hugepage, and if vmdq exists for hw based L2 dispatch, may we directly use buffer from virtqueue for hw DMA, so a totally zerocopy is obtained?

Several years before, intel submit a patch of similar idea to KVM, but not being accepted(lwn.net/Articles/413239/), I think the reason is too much change on kernel. Now with userspace vhost, we have a new chance to implement it.

More information about the dev mailing list