Re: newer (bug fixed) 4.3bsd tcp for Sun OS 3.3 available


weiser.pa@Xerox.COM
Fri, 25 Sep 87 14:19:23 PDT


Although Van Jacobson modestly states you don't want to run his code if
you have Sun 3.4, I continue to measure large performance differences in
extreme cases. I get the following times for transferring 10 megabytes
memory-to-memory (in other words, the client generates the bytes from
thin air, and the server puts them all into the same buffer):

33 secs SunOs 3.4
23 secs The Berkeley 4.3 + fixes courtesy of Van Jacobson, on top of
3.3.

This times are measured from Sun-3/260 to Sun-3/260 on the same
ethernet. Base load on the ethernet was 10-20%, so conceivably these
times could improve a bit.

I suspect that what accounts for the difference is that the SunOS 3.4
never seems to generate an ethernet packet larger 576 bytes or so when
operated through tcp, even though with UDP it generates the full 1500+
byte packets. netstat -i gives an MTU of 1500.

-mark



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