[ovs-dev] [PATCH 01/11] dpif: Pool dpif_recv() calls.

Ben Pfaff blp at nicira.com
Mon Feb 11 23:54:23 UTC 2013


On Mon, Feb 11, 2013 at 04:46:17PM +0200, Jarno Rajahalme wrote:
> Take ofproto-dpif upcall recv pooling down to the system call interface.
> 
> Signed-off-by: Jarno Rajahalme <jarno.rajahalme at nsn.com>

I tried this out with my test case.  I found that it yields a small
performance loss of about 3% with flow tables that just contain a
"normal" action and about the same with complicated flow tables that
contain multiple levels of resubmit.

I'm surprised that it produces such dramatically better results for
your test case.

Our test cases are quite different, though.  Yours has a constant rate
at the source, and measures the fraction of packets that makes it
through.  Mine essentially never drops a packet because it only sends
a new packet when the reply to a previous one has been received.  I am
not certain which is a better model for actual network behavior.  Do
you have any thoughts



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