Date: Thu, 16 Mar 2006 09:39:56 +0800 From: Chih-Chang Hsieh <cch@kmu.edu.tw> To: freebsd-net@freebsd.org Subject: Re: if_bridge + polling get lower througphts Message-ID: <4418C1EC.2030500@kmu.edu.tw> In-Reply-To: <20060315104807.GA20361@heff.fud.org.nz> References: <4417E97D.7050202@kmu.edu.tw> <20060315104807.GA20361@heff.fud.org.nz>
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Thanks a lot. We reset following MIBs: net.link.bridge.ipfw=0 net.link.bridge.pfil_member=0 net.link.bridge.pfil_bridge=0 For non-polling mode, the interrupt rate is down to 30%, For polling mode, the throughputs are as well as non-polling one and the interrupt rate is less than 10%. Andrew Thompson wrote: > On Wed, Mar 15, 2006 at 06:16:29PM +0800, Chih-Chang Hsieh wrote: > >> We have a FreeBSD 6.1-PRELEASE box. >> >> It runs with 2 em NICs and uses if_bridge + IPFW + ipfilter + pf. >> >> This box usually gets a very high interrupt rate >90%. >> >> By using netstat -I em0 1, we see: >> >> input (em0) output >> packets errs bytes packets errs bytes colls >> 15164 0 9549410 16842 0 12132262 0 >> 15331 0 9220723 17466 0 12354486 0 >> 16486 0 10089165 17926 0 13256014 0 >> 14936 10 8363433 17090 0 13367271 0 >> 14712 0 8449705 16701 0 13443079 0 >> >> >> When we enable the polling on em0 and em1 by ifconfig, netstat -I em0 shows: >> >> input (em0) output >> packets errs bytes packets errs bytes colls >> 10910 0 6629176 11467 0 7681346 0 >> 10951 0 6916042 11397 0 7954205 0 >> 11281 0 7437813 10804 0 7390386 0 >> 10711 0 6308033 11605 0 8400405 0 >> 10807 0 6270716 10973 0 7700748 0 >> >> the interrupt rate decreases (<30%) but we get lower throuphts. >> >> net.link.bridge.ipfw: 1 >> net.link.bridge.pfil_member: 1 >> net.link.bridge.pfil_bridge: 1 >> net.link.bridge.pfil_onlyip: 0 >> >> How could we tune the box to reach higher throughputs >> > > In the above setup you are running four packet filters, ipfilter, pf and > IPFW twice (ipfw=1 is an extra layer2 run). More specifically the packet filters > are actually invoked _10_ times per packet, in_if -> bridge_if -> out_if > per pfil_hook, plus the extra ipfw layer2. > > This explains your high cpu usage, you may want to reorganise the > filtering to optimise it. > > > Andrew > >
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