em0, polling performance, P4 2.8ghz FSB 800mhz

Don Bowman don at sandvine.com
Sun Feb 29 17:45:00 PST 2004

From: Mike Tancsa [mailto:mike at sentex.net]
> On Sat, 28 Feb 2004 23:17:44 -0500, in sentex.lists.freebsd.hackers >
> >If you want to spend more time in kernel, perhaps change
> >
> >I might have HZ @ 2500 as well.
> Hi,
> 	Just curious as to the reasoning behind that ?

@ high packet rates, you don't have enough DMA
queues available to the em driver, and will drop.
increasing the number of dma buffers will cause
problems with cache occupancy. Increasing the HZ
doesn't have a huge cost.

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