Date: Fri, 03 Oct 2008 13:46:22 -0400 From: Chuck Swiger <cswiger@mac.com> To: Pieter de Goeje <pdegoeje@service2media.com> Cc: freebsd-stable@freebsd.org, Bartosz Stec <admin@kkip.pl> Subject: Re: fxp performance with POLLING Message-ID: <48E65A6E.4090203@mac.com> In-Reply-To: <200810031706.11941.pdegoeje@service2media.com> References: <48E62ABA.6070901@kkip.pl> <200810031706.11941.pdegoeje@service2media.com>
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Pieter de Goeje wrote: > On Friday 03 October 2008, Bartosz Stec wrote: >> Hello again :) >> >> With POLLING enabled I experience about 10%-25% performance drop when >> copying files over network. Tested with both SAMBA and NFS. Is it normal? > > Yes. You don't want to use polling unless you set kern.hz to 10000 or > something in that range. HZ = 1000 or 2000 is fine for most purposes, at least up through T3 level bandwidth. For a home LAN or small business office of a half-dozen machines using DSL/Cable (~ 1-5 MBs up), even a P2-300 or VIA C3 600 at HZ=250 works OK as a firewall/router. The main thing that using polling does is that it adds a reasonably fixed amount of latency (ie, the poll interval) but gives solid processing performance even under heavy load, just as you say: > If you have a NIC with interrupt moderation, polling > should almost never be necessary. Note that polling can still be useful for > routers, because it allows you to have a much more responsive system even > when handling heavy network traffic. Note that he's got the link0 flag going, so that should mean he's using firmware with the fxp NIC which does interrupt moderation. Regards, -- -Chuck
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