tcp troughput weirdness

Danny Braniss danny at
Tue Jul 12 06:21:15 GMT 2005

while checking out the quality of a switch, I came about a very disturbing
dicovery: FreeBSD <-> Linux througput is MUCH better than FreeBSD <-> FreeBSD

	2 blades in the same bladeserver, A running FreeBSD 5.4, B running Linux
	C is running FreeBSD 5.4
	all are connected at 1gb.

	A -+ (FreeBSD)
	B -+ (Linux)
	    +---- [router] --- C (FreeBSD)
	A & B are on the same Vlan.
iperf results:
		Interval       Transfer     Bandwidth

A <=> B		0.0-10.0 sec  1.09 GBytes   939 Mbits/sec

A <=> C		0.0-10.0 sec   515 MBytes   432 Mbits/sec

B <=> C		0.0-10.0 sec  1.07 GBytes   918 Mbits/sec

I've run the tests several times, and the numbers are very similar,
so BIG Question: is there anything that can be tunned on the FreeBSD to
better the throughput?



More information about the freebsd-net mailing list