On Thu, 2011-02-03 at 07:59 +0200, Michael S. Tsirkin wrote: > > Let's look at the sequence here: > > > > guest start_xmit() > > xmit_skb() > > if ring is full, > > enable_cb() > > > > guest skb_xmit_done() > > disable_cb, > > printk free_old_xmit_skbs <-- it was between more than 1/2 > to > > full ring size > > printk vq->num_free > > > > vhost handle_tx() > > if (guest interrupt is enabled) > > signal guest to free xmit buffers > > > > So between guest queue full/stopped queue/enable call back to guest > > receives the callback from host to free_old_xmit_skbs, there were > about > > 1/2 to full ring size descriptors available. I thought there were > only a > > few. (I disabled your vhost patch for this test.) > > > The expected number is vq->num - max skb frags - 2. It was various (up to the ring size 256). This is using indirection buffers, it returned how many freed descriptors, not number of buffers. Why do you think it is vq->num - max skb frags - 2 here? Shirley -- 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
