Date: Tue, 01 Oct 2002 12:44:55 -0700 From: Eli Dart <dart@nersc.gov> To: net@freebsd.org Subject: limit to data in flight Message-ID: <20021001194455.552A33B1AE@gemini.nersc.gov>
next in thread | raw e-mail | index | archive | help
[-- Attachment #1 --] Hi all, I'm seeing something strange here... I have a freebsd box running iperf (4.6-RELEASE-p1, iperf 1.6.2 with pthreads patches). When attempting to use a 1MB tcp window, the box won't put more than 256kB in flight after the first connection to a given host. I seem to remember hearing/reading/whatever that freebsd keeps track of congestion stats for a route in the kernel routing table and primes the congestion window for new sockets to the same destination with the previous values (thus eliminating a congestion avoidance cycle on each new socket). High-bandwidth connections between the hosts in question (the other is a linux box of indeterminate recent version) do hit congestion the first time. However, in this particular case (since this is a test machine that we use to diagnose network problems) I'd like to be able to turn it off. I didn't see anything in sysctl that looked obvious, but I'm perfectly willing to believe I missed it. So, can this be turned off? Also, what is the timeout on this data in the kernel? Thanks! --eli ------------------------------------------------------------------------ Eli Dart Office: (510) 495-2999 NERSC Networking and Security Group Cell: (510) 703-4508 Lawrence Berkeley National Laboratory Fax: (510) 486-4316 PGP Key fingerprint = C970 F8D3 CFDD 8FFF 5486 343A 2D31 4478 5F82 B2B3 ------------------------------------------------------------------------ [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (FreeBSD) Comment: This is a comment. iD8DBQE9mfs3LTFEeF+CsrMRApNtAJ91gjpPKcyzAbA3kP/B3rRBxvYYwACeLXPM kzNpTNjLg0sq7MdycvG++Bk= =Oe6o -----END PGP SIGNATURE-----
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20021001194455.552A33B1AE>