On Thu, Nov 3, 2011 at 10:38 AM, Ansis Atteka <[email protected]> wrote: > > > On Wed, Nov 2, 2011 at 6:36 PM, Jesse Gross <[email protected]> wrote: >> >> On Wed, Nov 2, 2011 at 5:13 PM, Ansis Atteka <[email protected]> wrote: >> > On Wed, Nov 2, 2011 at 3:49 PM, Jesse Gross <[email protected]> wrote: >> >> >> >> On Mon, Oct 31, 2011 at 5:00 PM, Ansis Atteka <[email protected]> >> >> wrote: >> >> > UDP performance is currently limited to much lower numbers than for >> >> > TCP. >> >> > This could be improved in future releases. The cause for UDP >> >> > performance >> >> > penalty is: >> >> > >> >> > python uses much smaller buffers in sendto() function, and >> >> > UDP-flow control is implemented on events which are timer triggered; >> >> >> >> I think this is not that big of a deal. Since this test is primarily >> >> about vlans and not performance, the absolute number isn't really that >> >> important. This is particularly true with UDP where for a given size >> >> I would expect it to either work or not. >> >> >> >> UDP also almost always has lower performance than TCP anyways because >> >> there are fewer offloads. >> >> >> >> I see that you still have a fixed set of sizes to try for UDP packets, >> >> did you look into detecting the MTU? >> > >> > Yes, the correct way to do this is to use SIOCGIFMTU on the interface >> > which >> > will be used by UDP sender socket (Although this is not POSIX >> > standardized). >> > >> > But, I still somehow must be able to figure out which interface will be >> > actually used >> > by the UDP sender socket. I can make an assumption here by simply using >> > the >> > Test IP address which user specified when he started ovs-test client. In >> > my >> > opinion >> > this should work most of the time. >> >> You mean via a routing table lookup through ip or route? I agree that >> that is good enough for a test tool. > > I meant to use ioctl() calls from Python: > > SIOCGIFCONF to get mapping from IP addresses to interfaces; and then > SIOCGIFMTU to get MTU for a particular interface. > > The only thing is that I must be careful to interpret ioctl() output in a > platform dependent way.
SIOCGIFCONF just gives you the addresses associated with an interface. If you want to know the interface associated with a destination address, you'll need to do a routing table lookup since the exact address won't be on any of the local devices. _______________________________________________ dev mailing list [email protected] http://openvswitch.org/mailman/listinfo/dev
