Date: Mon, 3 Jun 2002 01:59:13 -0400 (EDT) From: Nguyen-Tuong Long Le <le@cs.unc.edu> To: freebsd-net@freebsd.org Subject: Problem with SYN cache in FreeBSD 4.5 Message-ID: <Pine.GSO.4.10.10206030156290.20082-100000@capefear.cs.unc.edu>
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Hi all, Our group has a proprietary web server that can handle 10000 requests/s under FreeBSD 4.3 release. We recently upgraded our system to 4.5 and got very poor performance. While the web server runs, I see lots of messages similar to the following on the console "Limiting open port RST response from 1068 to 200 packets per second". The problem seems to be related to the syncache implementation that drops incoming SYN segments. I've tried to increase the size of the hash table but that didn't seem to help much. Here is the output of "sysctl net.inet.tcp.syncache". net.inet.tcp.syncache.bucketlimit: 512 net.inet.tcp.syncache.cachelimit: 262142 net.inet.tcp.syncache.count: 3 net.inet.tcp.syncache.hashsize: 512 net.inet.tcp.syncache.rexmtlimit: 3 (I'm puzzled why SYNs are dropped while the net.inet.tcp.syncache.count is so low). kern.ipc.somaxconn and kern.ipc.nmbclusters are set to 8192 and 65536 respectively. Any help would be very much appreciated! Thanks, -- long P.S. Please kindly cc' your reply to me since I'm not on the list. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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