From: aurel32 <aurel32@c046a42c-6fe2-441c-8c8c-71466251a162>
Date: Mon, 5 May 2008 21:26:43 +0000 (+0000)
Subject: qemu: generate signals on tap I/O
X-Git-Tag: xen-3.3.0-rc1~194^2^2~111
X-Git-Url: http://xenbits.xensource.com/gitweb?a=commitdiff_plain;h=603d3e79b2c64bceb8826d3d65b525188db47797;p=qemu-xen-3.3-testing.git

qemu: generate signals on tap I/O

Currently tap does not generate signals on I/O; this causes
network latency to be dependent on the timer tick (1ms without
dyntick, guest dependent with dyntick).  By generating a signal
on I/O, we can inform the guest immediately that a packet has
arrived.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>


git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@4341 c046a42c-6fe2-441c-8c8c-71466251a162
---

diff --git a/vl.c b/vl.c
index ea8c63c5..f752a3b7 100644
--- a/vl.c
+++ b/vl.c
@@ -4030,6 +4030,7 @@ static TAPState *net_tap_fd_init(VLANState *vlan, int fd)
     if (!s)
         return NULL;
     s->fd = fd;
+    enable_sigio_timer(fd);
     s->vc = qemu_new_vlan_client(vlan, tap_receive, NULL, s);
     qemu_set_fd_handler(s->fd, tap_send, NULL, s);
     snprintf(s->vc->info_str, sizeof(s->vc->info_str), "tap: fd=%d", fd);