From owner-freebsd-net Wed Sep 29 13: 7:15 1999 Delivered-To: freebsd-net@freebsd.org Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by hub.freebsd.org (Postfix) with SMTP id F196715955 for ; Wed, 29 Sep 1999 13:06:57 -0700 (PDT) (envelope-from luigi@labinfo.iet.unipi.it) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id NAA04648; Wed, 29 Sep 1999 13:43:43 +0100 From: Luigi Rizzo Message-Id: <199909291243.NAA04648@labinfo.iet.unipi.it> Subject: large window performance... To: net@freebsd.org Date: Wed, 29 Sep 1999 13:43:43 +0100 (MET) X-Mailer: ELM [version 2.4 PL23] Content-Type: text Content-Length: 1404 Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org not sure if this is a known feature, but a few times i have heard of alleged problems with TCP and large windows. While working on PGM i had a siilar problem -- apparently i could not make use of the whole socket buffer until i moved kern.ipc.maxsockbufsize from 256K to some much larger value. After a bit of investigation: kern.ipc.maxsockbufsize limits the amount of buffer space you can have on a socket. in my particular app i was using 530 byte packets, and they were stored in a cluster (2KB), with a rather large waste of space. The 256K limit caused my app to be able to use only 128 buffers (actually less because also MBUFs are accounted). I just wanted to mentionit as this problem might hit other people. This is on a 3.1R system, maybe the thing is fixed in more recent versions of FreeBSD (not sure, there is a sock_waste_factor variable which might be of some help here and maybe is just misused in 3.1R) cheers luigi -----------------------------------+------------------------------------- Luigi RIZZO, luigi@iet.unipi.it . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy) http://www.iet.unipi.it/~luigi/ngc99/ ==== First International Workshop on Networked Group Communication ==== -----------------------------------+------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message