Jesse, Potentially we could add iperf TCP tests to the ovs-vlan-test and then IP packet length would match MTU? Albeit then iperf would not report packet-loss or out-of-order packet count.
During the implementation I had following concerns: 1. ovs-vlan-test utility uses iperf's STDOUT, STDERR to communicate with it and that might be iperf-version specific. Preferred approach would be to use some kind of a "iperf-type"-library, but I was not able to find one (maybe we could develop one ourselves?). 2. Iperf also has limitation that smallest UDP packet it can send is 52-bytes Thanks, Ansis On Wed, Oct 19, 2011 at 11:21 AM, Jesse Gross <je...@nicira.com> wrote: > On Tue, Oct 18, 2011 at 9:23 PM, Ansis Atteka <aatt...@nicira.com> wrote: > > ovs-vlan-test runs through a number of tests to identify VLAN issues. > This > > is useful when trying to debug why a particular driver has issues, but it > made > > the testing environment a bit harder to set up. This commit adds an > iperf > > test to check basic functionality. It also useful in detecting > performance > > issues. > > > > Issue #6976 > > I didn't review the implementation details but I have some high level > concerns about the tests being run: > * At least some of the problems that we have encountered are due to > offloading and some offloads are only available with TCP. Therefore, > running only UDP traffic won't catch these. > * Another category of issues has do with exactly MTU sized packets. > I see that the packet sizes you use are the same as the previous > version but I'm not sure that they are great choices. The first issue > is that it is essentially assuming that the MTU is 1500 but ideally we > would actually detect it. Once we have it, I would pick a value that > is exactly MTU size after accounting for the UDP headers. Right now > we will probably get that but you have to assume that fragmentation > results in a maximum size first packet. >
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