Hi Dor, How are you measuring performance? The numbers I've gotten with netperf before and after your patch are:
tx - 647.27mbit rx - 89.22 tx - 27.82 rx - 79.93 So this patch is pretty much killing performance for netperf. Dor Laor wrote: > There was a problem with the location of the notify call in > add_buff function: > When VRING_USED_F_NO_NOTIFY is set, the host does not kick the > guest when packets were transmitted, as a result the guest runs > out of tx buffers sometimes. But even if F_NO_NOTIFY is set, if the tx buffer is full, we notify the guest, so this prevents that from happening. > This is fine but the problem lies > when add_buf fails, it called notify and the host sends all the > pending tx pkts. When enable_cb was called, more_used(vq) returned > false so eventually the skb was dropped. > I'm having a tough time following this part. If add_buf fails, we notify unconditionally (which is, I think what we want). I'm not sure how that relates to a packet getting dropped though. Regards, Anthony Liguori ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
