On Thu, May 02, 2013 at 09:13:29AM +0530, nitesh narayan lal wrote: > Hi, > I am currently working on the virtio performance analysis in PowerPC . That's nice. > I was looking at the virtio front-end code and had done tracing by > adding WARN_ON condition in skb_recv_done(),xmit_skb_done( > ) and virtqueue_kick(). That's a bit heavy-handed. Why not just use ftrace? > What I had seen is virtqueue_kick() internally it calls iowrite16() > which will cause an exit to QEMU, You probably should be looking at vhost-net and not userspace virtio-net if you are interested in performance. > now either I send a packets from > Guest or receive a packets to guest sart_xmit() will be called and > inside start_xmit there is a call to virtqueue_kick() causing Guest > exit. Also for every packet or ack sent from Guest there is an > exception received while sending or receiving the next packet/ack. Not exactly, we can buffer many events in case guest and host are running in parallel. See vring_need_event and its uses. > Due to all of the above factors mentioned their will be an increase in > signal, EXTINT and guest exits Increase as compared to what? > and hence it will effect the CPU > performance. > This is what my analysis is so far, it would be great if I could get > some help on this such that whether it seems appropriate or not ? > Regards > Nitesh Narayan Lal > _______________________________________________ > Virtualization mailing list > Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/virtualization -- 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
