Date: Thu, 09 May 2013 21:55:42 +0700 From: Eugene Grosbein <egrosbein@rdtc.ru> To: =?UTF-8?B?IkNsw6ltZW50IEhlcm1hbm4gKG5vZGVucyki?= <nodens2099@gmail.com> Cc: freebsd-net@freebsd.org Subject: Re: High CPU interrupt load on intel I350T4 with igb on 8.3 Message-ID: <518BB8EE.2080705@rdtc.ru> In-Reply-To: <517A657B.7060003@gmail.com>
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On 26.04.2013 18:31, "Clément Hermann (nodens)" wrote: > Hi list, > > We use pf+ALTQ for trafic shaping on some routers. > > We are switching to new servers : Dell PowerEdge R620 with 2 8-cores > Intel Processor (E5-2650L), 8GB RAM and Intel I350T4 (quad port) using > igb driver. The old hardware is using em driver, the CPU load is high > but mostly due to kernel and a large pf ruleset. > > On the new hardware, we see high CPU Interrupt load (up to 95%), even > though there is not much trafic currently (peaks about 150Mbps and > 40Kpps). All queues are used and binded to a cpu according to top, but a > lot of CPU time is spent on igb queues (interrupt or wait). The load is > fine when we stay below 20Kpps. > > We see no mbuf shortage, no dropped packet, but there is little margin > left on CPU time (about 25% idle at best, most of CPU time is spent on > interrupts), which is disturbing. It seems you suffer from pf lock contention. You should stop using pf with multi-core systems with 8.3. Move to ipfw+dummynet or ng_car for 8.3 or move to 10.0-CURRENT having new, rewritten pf that does not have this problem. Network device driver is not guilty here, that's just pf's contention running in igb's context. Eugene Grosbeinhome | help
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