Date: Tue, 28 Apr 2009 10:09:57 +0200 From: Fabien Thomas <fabien.thomas@netasq.com> To: barney_cordoba@yahoo.com Cc: freebsd-net@freebsd.org, Ed Maste <emaste@freebsd.org> Subject: Re: Interrupts + Polling mode (similar to Linux's NAPI) Message-ID: <F14F044E-B39E-476B-A9DE-0EDB4D5265BE@netasq.com> In-Reply-To: <160513.83122.qm@web63904.mail.re1.yahoo.com> References: <160513.83122.qm@web63904.mail.re1.yahoo.com>
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--Apple-Mail-148-605993175 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit To share my results: I have done at work modification to the polling code to do SMP polling (previously posted to this ml). SMP polling (dynamic group of interface binded to CPU) does not significantly improve the throughput (lock contention seems to be the cause here). The main advantage of polling with modern interface is not the PPS (which is nearly the same) but the global efficiency of the system when using multiple interfaces (which is the case for Firewall). The best configuration we have found with FreeBSD 6.3 is to do polling on one CPU and keep the other CPU free for other processing. In this configuration the whole system is more efficient than with interrupt where all the CPU are busy processing interrupt thread. Regards, Fabien --Apple-Mail-148-605993175--
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