XEN: switch from using phy: to tap:aio: to improve block IO performance

Thanks to Berthold for the hint (test case time was reduced by > 30%)

diff --git a/build b/build
index f647779..42ab92b 100755 (executable)
--- a/build
+++ b/build
@@ -1409,12 +1409,12 @@ for SPECFILE in "${SPECFILES[@]}" ; do
 
        if [ "$VM_TYPE" = 'xen' ]; then
                XMROOT="file:$(readlink -f $VM_IMAGE)"
-               XMROOT=${XMROOT/#file:\/dev/phy:/dev}
+               XMROOT=${XMROOT/#file:\/dev/tap:aio:/dev}
                XMROOT="disk=$XMROOT,hda1,w"
                XMSWAP=
                if test -n "$VM_SWAP" ; then
                    XMSWAP="file:$(readlink -f $VM_SWAP)"
-                   XMSWAP=${XMSWAP/#file:\/dev/phy:/dev}
+                   XMSWAP=${XMSWAP/#file:\/dev/tap:aio:/dev}
                    XMSWAP="disk=$XMSWAP,hda2,w"
                fi
                XENID="${VM_IMAGE%/root}"