Date: Fri, 14 Aug 2009 14:55:19 +0100 (BST) From: Robert Watson <rwatson@FreeBSD.org> To: Tom Uffner <tom@uffner.com> Cc: pf@freebsd.org, current@freebsd.org Subject: Re: packet forwarding/firewall performance question Message-ID: <alpine.BSF.2.00.0908141452040.82989@fledge.watson.org> In-Reply-To: <4A8484E4.6090504@uffner.com> References: <4A8484E4.6090504@uffner.com>
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On Thu, 13 Aug 2009, Tom Uffner wrote: > i'm hoping a few people will give me estimates on what kind of throughput i > should theoretically expect before i provide any actual test data. > > also, any suggestions on tuning would be welcome. > > so far in preliminary tests, enabling polling on the network interfaces > reduces my performance slightly both to/from and through the box. > net.inet.ip.fastforwarding doesn't seem to make much difference either > way but i haven't done very thorough testing of it. increasing > net.inet.tcp.sendbuf_max & recvbuf_max may have helped, but again, not > sufficiently tested. I can't speak to absolute numbers, but I wouldn't expect net.inet.tcp.* changes to make any difference, as they should affect only locally terminated sockets on the firewall host, not forwarded packets. You might want to try experimenting with net.isr.direct -- try setting it to 0, as this changes the kernel dispatch model for the network stack. On a UP box, I would probably anticipate a performance loss for making that change, or similar configuration changes for multiple netisr threads using net.isr.maxthreads. If you're using firewall code, fast forwarding is unlikely to make a difference. Depending on the cache/memory/CPU trade-off, you might find turning off flowtable support helps -- net.inet.flowtable.enable=0. Robert N M Watson Computer Laboratory University of Cambridge
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