Messages in this thread | | | Date | Mon, 29 Mar 2010 09:57:33 -0700 | From | Rick Jones <> | Subject | Re: Network performance - iperf |
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Rick Jones wrote: > I don't know how to set fixed socket buffer sizes in iperf, if you were > running netperf though I would suggest fixing the socket buffer sizes > with the test-specific -s (affects local) and -S (affects remote) options: > > netperf -t TCP_STREAM -H <remote> -l 30 -- -s 32K -S 32K -m 32K > > to test the hypothesis that the autotuning of the socket buffers/window > size is allowing the windows to grow in the larger memory cases beyond > what the TLB in your processor is comfortable with.
BTW, by default, netperf will allocate a "ring" of send buffers - the number allocated will be one more than the socket buffer size divided by the send size - so in the example above, there will be two 32KB buffers allocated in netperf's send ring. A similar calculation may happen on the receive side.
That can be controlled via the global (before the "--") -W option.
-W send,recv Set the number of send,recv buffers
So, you might make the netperf command:
netperf -t TCP_STREAM -H <remote> -l 30 -W 1,1 -- -s 32K -S 32K -m 32K
happy benchmarking,
rick jones
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