Date: Wed, 26 Dec 2007 13:08:57 -0800 From: "Jack Vogel" <jfvogel@gmail.com> To: "Nash Nipples" <trashy_bumper@yahoo.com> Cc: freebsd-net@freebsd.org Subject: Re: Maximum NIC interrupts Message-ID: <2a41acea0712261308y7ac8d831i4e02c7849bbca3f6@mail.gmail.com> In-Reply-To: <508610.85778.qm@web36309.mail.mud.yahoo.com> References: <508610.85778.qm@web36309.mail.mud.yahoo.com>
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On Dec 26, 2007 8:10 AM, Nash Nipples <trashy_bumper@yahoo.com> wrote: > Dear Jordi, > > In theory, on a Gigabit link you get 1 000 000 000 bits * second. > By default you have the MTU set to 1500 bytes which makes ~12 000 bits. > 1 000 000 000 / 12 000 = ~ 83 333 packets per second. > 83 333 packets per second makes 0.083333 packets per microsecond. > 1 / 0.08333 = 12.0 microseconds per packet. Thus one can interrupt CPU > at a rate of ~83 333 times per second. If you use lower packets sizes you > might get even more funny numbers. > > 8000 is a quiet low number. The driver was developed by guys > at Intel. I don't see a reason to worry. > > By the way they have products with Interrupt Moderation. > http://www.intel.com/design/network/applnots/ap450.htm Yes, one of the items in my queue is AIM, adaptive interrupt moderation, the Linux driver has this, my coworker Jesse Brandeburg developed that code, and I hope to do something similar for the em driver. Anyway, I'm still on vacation and don't want to distract myself from music, but look for AIM sometime this new year :) Jack
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