Date: Mon, 3 Jun 2002 12:13:32 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Nguyen-Tuong Long Le <le@cs.unc.edu> Cc: freebsd-net@freebsd.org Subject: Re: Problem with SYN cache in FreeBSD 4.5 Message-ID: <20020603121118.Y38431-100000@patrocles.silby.com> In-Reply-To: <Pine.GSO.4.10.10206030156290.20082-100000@capefear.cs.unc.edu>
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On Mon, 3 Jun 2002, Nguyen-Tuong Long Le wrote: > 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". A few questions: 1. Is this 4.5-release, or 4.5-stable (aka 4.6-RC2)? 4.5-release had a few bugs in the syn cache which could cause crashes. 2. Are you using accept filters? Accept filters act oddly on 4.5-release, you'll have to upgrade to 4.5-stable/4.6. 3. Could you use tcpdump to determine what exactly is going wrong and post a url to the log so that we can investigate what is going wrong? Thanks, Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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