Date: Sat, 12 Sep 2009 12:27:18 +0500 From: rihad <rihad@mail.ru> To: freebsd-net@freebsd.org Subject: [POLLING] strange interrupt/system load Message-ID: <4AAB4D56.30207@mail.ru>
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The box experiences ~230 mbit/s traffic flow through it. I've doubled some sysctls after reading polling(4): kern.polling.each_burst=10 # was: 5 kern.polling.burst_max=350 # was: 150 FreeBSD 7.2-RELEASE-p3 amd64 HZ=1000 Now for the fun part. With kern.polling.idle_poll = 1 top shows: CPU: 0.0% user, 0.0% nice, 26.9% system, 3.1% interrupt, 70.0% idle ~8000 interrupts/s total according to systat -vmstat: 1999 cpu0: time 2000 cpu1: time 1999 cpu2: time 1999 cpu3: time With kern.polling.idle_poll = 0 top shows: CPU: 0.0% user, 0.0% nice, 0.0% system, 13.9% interrupt, 86.0% idle Still the same ~8000 clock interrupts/s. Under both scenarios polling is enabled on both em0 and em1 through ifconfig. 1) Why is the interrupt load relatively high with polling enabled? 2) How come 13.9% interrupts are not also in the first scenario if their total rate is the same (~8000)? Thanks.
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