Date: Wed, 19 Jul 2006 22:38:56 -0400 From: Ed Maste <emaste@phaedrus.sandvine.ca> To: Marcelo Gardini do Amaral <marcelo@registro.br> Cc: freebsd-stable@freebsd.org Subject: Re: How to setup polling on 'bge' interface Message-ID: <20060720023856.GA65960@sandvine.com> In-Reply-To: <20060711190908.GC69272@registro.br> References: <20060711190908.GC69272@registro.br>
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On Tue, Jul 11, 2006 at 04:09:08PM -0300, Marcelo Gardini do Amaral wrote: > Hi, > > I'm trying to setup polling in my box. [...] > But I always get some packet loss. A few points: - Polling and SMP are compatible in 6.1. In fact, they were compatible in earlier versions too; basically it's just the compile-time check that had to be "fixed." - You may have to adjust some parameters in the kern.polling sysctl tree - specifically, kern.polling.burst_max, kern.polling.each_burst and kern.polling.user_frac might need tweaking. - The polling feedback algorithm does not work very well if your workload is focused largely on per-packet tasks (such as routing or bridging). You'll find that there is still idle CPU time at the point you start dropping packets. I have some work in progress to address this, but it's not yet committed. - Polling's major advantage is the avoidance of livelock on UP systems, and not improved performance. What level of traffic are you putting through this box? Is it routing/ bridging, or an endpoint like a web server? Ed Maste
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