From: Michael S. Tsirkin <mst@redhat.com>
Date: Thu, 19 May 2011 23:10:44 +0000 (+0300)
Subject: virtio_ring: support event idx feature
X-Git-Tag: v3.0-rc2~23^2~4
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a5c262c5fd83ece01bd649fb08416c501d4c59d7;p=pandora-kernel.git

virtio_ring: support event idx feature

Support for the new event idx feature:
1. When enabling interrupts, publish the current avail index
   value to the host to get interrupts on the next update.
2. Use the new avail_event feature to reduce the number
   of exits from the guest.

Simple test with the simulator:

[virtio]# time ./virtio_test
spurious wakeus: 0x7

real    0m0.169s
user    0m0.140s
sys     0m0.019s
[virtio]# time ./virtio_test --no-event-idx
spurious wakeus: 0x11

real    0m0.649s
user    0m0.295s
sys     0m0.335s

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

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