Date: Fri, 4 Jul 2008 13:16:13 +0200 (CEST) From: Ingo Flaschberger <if@xip.at> To: Paul <paul@gtcomm.net> Cc: FreeBSD Net <freebsd-net@freebsd.org> Subject: Re: Freebsd IP Forwarding performance (question, and some info) [7-stable, current, em, smp] Message-ID: <alpine.LFD.1.10.0807041303490.20760@filebunker.xip.at> In-Reply-To: <486DF1A3.9000409@gtcomm.net> References: <4867420D.7090406@gtcomm.net> <20080701010716.GF3898@stlux503.dsto.defence.gov.au> <alpine.LFD.1.10.0807010308320.19444@filebunker.xip.at> <486986D9.3000607@monkeybrains.net> <48699960.9070100@gtcomm.net> <ea7b9c170806302005n2a66f592h2127f87a0ba2c6d2@mail.gmail.com> <20080701033117.GH83626@cdnetworks.co.kr> <ea7b9c170806302050p2a3a5480t29923a4ac2d7c852@mail.gmail.com> <4869ACFC.5020205@gtcomm.net> <4869B025.9080006@gtcomm.net> <486A7E45.3030902@gtcomm.net> <486A8F24.5010000@gtcomm.net> <486A9A0E.6060308@elischer.org> <486B41D5.3060609@gtcomm.net> <alpine.LFD.1.10.0807021052041.557@filebunker.xip.at> <486B4F11.6040906@gtcomm.net> <alpine.LFD.1.10.0807021155280.557@filebunker.xip.at> <486BC7F5.5070604@gtcomm.net> <20080703160540.W6369@delplex.bde.org> <486C7F93.7010308@gtcomm.net> <20080703195521.O6973@delplex.bde.org> <486D35A0.4000302@gtcomm.net> <alpine.LFD.1.10.0807041106591.19613@filebunker.xip.at> <486DF1A3.9000409@gtcomm.net>
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Dear Paul, >>> what could cause this? >> >> *) kern.polling.idle_poll enabled? >> *) kern.polling.user_frac ? >> *) kern.polling.reg_frac ? >> *) kern.polling.burst_max ? >> *) kern.polling.each_burst ? > > I tried tons of different values for these and nothing made any significant > difference. > Idle polling makes a difference, allows more pps, but still errors. > Without idle polling it seems PPS is limited to HZ * descriptors, or 1000 * > 256 or 512 > but 1000 * 1024 is the same as 512.. 4000 * 256 or 2000 * 512 works but > starts erroring 600kpps (SMP right now but it happens in UP too) I have patched src/sys/kern/kern_poll.c to support higher burst_max values: #define MAX_POLL_BURST_MAX 10000 When setting kern.polling.burst_max to higher values, the server reach a point, where cpu-usage goes up without load, so try to keep below this values. I also have set the network card to 4096 rx-"ram", to have more room for late polls. Kind regards, Ingo Flaschberger
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