Date: Fri, 30 Jan 2004 14:00:00 -0800 From: Eli Dart <dart@nersc.gov> To: Mike Hunter <mhunter@ack.Berkeley.EDU> Cc: freebsd-net@freebsd.org Subject: Re: Assymetric results from iperf across gigabit link (long) Message-ID: <20040130220000.81179F8EB@gemini.nersc.gov> In-Reply-To: Message from Mike Hunter <mhunter@ack.Berkeley.EDU> <20040130213935.GB25194@ack.Berkeley.EDU>
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--==_Exmh_-966797664P Content-Type: text/plain; charset=us-ascii In reply to Mike Hunter <mhunter@ack.Berkeley.EDU> : > On Jan 30, "To freebsd-net@freebsd.org" wrote: > > > Hi, > > [snip] > > I switched the two pieces of hardware, and the photons still prefer going > uphill, so maybe there's a problem with the fiber after all. I'd still > appreciate any hints on what to ask freebsd to help me figure it out. > (Yes, we have real fiber test gear, this is more of an experiment.) Have you looked at interface error counts? (netstat -inbd) If you have dirty fiber, you could just be missing/corrupting the odd packet here and there, which would be enough to impact a high-bandwidth TCP flow. the other thing to check is if a UDP cannon has the same bandwidth asymmetry, since the UDP iperf tests don't have TCP's timidity (if memory serves me).... --eli > > Thanks, > > Mike > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" > --==_Exmh_-966797664P Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.3 (FreeBSD) Comment: Exmh version 2.5 07/13/2001 iD8DBQFAGtPgLTFEeF+CsrMRAq2sAJ9uFiOjntj/guvuzA21Cfjn7j9y4gCgwB/d kPdNA34Mhgy2Z1+lv9QCg1w= =u9Kc -----END PGP SIGNATURE----- --==_Exmh_-966797664P--
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