On 18.02.2013 13:39, Peter Lieven wrote:
On 15.02.2013 14:32, Stefan Hajnoczi wrote:
On Fri, Feb 15, 2013 at 10:32:31AM +0100, Peter Lieven wrote:
historically the kernel queues packets two times. once
at the device and second in qdisc. this is believed to cause
interface stalls if one of these queues overruns.
setting IFF_ONE_QUEUE is the default in kernels >= 3.8. the
flag is ignored since then. see kernel commit
5d097109257c03a71845729f8db6b5770c4bbedc
v2:
- do only set the flag on linux as it breaks macvtap
- define IFF_ONE_QUEUE in tap-linux.h
Signed-off-by: Peter Lieven <p...@kamp.de>
---
net/tap-linux.c | 4 ++++
net/tap-linux.h | 1 +
2 files changed, 5 insertions(+)
diff --git a/net/tap-linux.c b/net/tap-linux.c
index a953189..d49f2fd 100644
--- a/net/tap-linux.c
+++ b/net/tap-linux.c
@@ -51,6 +51,10 @@ int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+#ifdef __linux__
+ ifr.ifr_flags |= IFF_ONE_QUEUE;
+#endif
tap-linux.c <--- notice the filename
Perhaps the solution is to try with IFF_ONE_QUEUE. If the result is
-EINVAL, try without.
Is IFF_ONE_QUEUE queryable with ioctl(fd, TUNGETFEATURES, &features) ?
Peter
Anyone?
Thanks,
Peter
