main: force enabling of I/O thread

Enabling the I/O thread by default seems like an important part of declaring
1.0.  Besides allowing true SMP support with KVM, the I/O thread means that the
TCG VCPU doesn't have to multiplex itself with the I/O dispatch routines which
currently requires a (racey) signal based alarm system.

I know there have been concerns about performance.  I think so far the ones that
have come up (virtio-net) are most likely due to secondary reasons like
decreased batching.

I think we ought to force enabling I/O thread early in 1.0 development and
commit to resolving any lingering issues.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 0 insertions, 4 deletions

diff --git a/hw/qxl.c b/hw/qxl.c
index 1d9077db68..45e24016fc 100644
--- a/hw/qxl.c
+++ b/hw/qxl.c
@@ -1388,11 +1388,7 @@ static void init_pipe_signaling(PCIQXLDevice *d)
        dprint(d, 1, "%s: pipe creation failed\n", __FUNCTION__);
        return;
    }
-#ifdef CONFIG_IOTHREAD
    fcntl(d->pipe[0], F_SETFL, O_NONBLOCK);
-#else
-   fcntl(d->pipe[0], F_SETFL, O_NONBLOCK /* | O_ASYNC */);
-#endif
    fcntl(d->pipe[1], F_SETFL, O_NONBLOCK);
    fcntl(d->pipe[0], F_SETOWN, getpid());