Date: Wed, 29 Sep 1999 13:43:43 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: net@freebsd.org Subject: large window performance... Message-ID: <199909291243.NAA04648@labinfo.iet.unipi.it>
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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
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