Date: Fri, 16 Jul 1999 15:08:41 -0700 (PDT) From: Ken Bolingbroke <ken@bolingbroke.com> To: hackers@freebsd.org Subject: Benchmarking server app on FreeBSD Message-ID: <Pine.BSF.4.05.9907161344570.20960-100000@mich.bolingbroke.com>
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I'm benchmarking the performance of a server application on various platforms. To do so, I've developed a program on FreeBSD 3.x to generate heavy loads. This program can, for example, generate 200 simultaneous connections to the server and process them all appropriately, and I have it running on a bunch of machines to simulate high load on the server. However, I'm running into an unexpected problem on a server running FreeBSD 3.2-RELEASE. If a single client opens 200 simultaneous connections to the FreeBSD server, all but 30 to 40 of those get an immediate "Connection refused". If a whole row of clients open 200 simultaneous connections each, they still get only 30 to 40 each, but the server is now accepting upwards of 200 connections all at once. This seems to indicate that it's not a server load question, but rather that the server will not accept more than ~40 connections at once from the same client. I've tried the same test using the FreeBSD clients against a Solaris server, and the Solaris server accepts all 200 connections from each client machine without refusing any connections, so I'm sure it's not on the client end. A fellow admin suggested that my load simulation program quite possibly looks like a SYN attack and FreeBSD might be rejecting it for that reason. Since Solaris doesn't have the same SYN attack protection, that would account for the difference. If this is the case, how would I disable the SYN attack protection for these tests? Or is it something else limiting FreeBSD? For reference, the FreeBSD server has a custom kernel compiles with MAXUSERS set to 512, and other performance enhancements I've gleaned off these lists. Thanks, Ken Bolingbroke hacker@bolingbroke.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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