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.
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