Il 06/09/2012 07:02, Michael S. Tsirkin ha scritto: >> > It might be worth just unconditionally having a cache for the 2 >> > descriptor case. This is what I get with qemu tap, though for some >> > reason the device features don't have guest or host CSUM, so my setup is >> > probably screwed: > Yes without checksum net core always linearizes packets, so yes it is > screwed. > For -net, skb always allocates space for 17 frags + linear part so > it seems sane to do same in virtio core, and allocate, for -net, > up to max_frags + 1 from cache. > We can adjust it: no _SG -> 2 otherwise 18. > > Not sure about other drivers, maybe really use 2 there for now. 2 should also be good for virtio-blk and virtio-scsi 4KB random rw workloads. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
