Date: Wed, 15 Mar 2006 18:16:29 +0800 From: Chih-Chang Hsieh <cch@kmu.edu.tw> To: freebsd-net@freebsd.org Subject: if_bridge + polling get lower througphts Message-ID: <4417E97D.7050202@kmu.edu.tw>
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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. The related sysctl MIBs are: kern.polling.idlepoll_sleeping: 1 kern.polling.stalled: 0 kern.polling.suspect: 0 kern.polling.phase: 0 kern.polling.enable: 0 kern.polling.handlers: 0 kern.polling.residual_burst: 0 kern.polling.pending_polls: 0 kern.polling.lost_polls: 0 kern.polling.short_ticks: 0 kern.polling.reg_frac: 20 kern.polling.user_frac: 50 kern.polling.idle_poll: 1 kern.polling.each_burst: 5 kern.polling.burst_max: 1000 kern.polling.burst: 5 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 as in non-polling mode? Thanks in advance.
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