Intel 82574L (em)

[hiren panchasara]

On Fri, Jan 30, 2015 at 01:11:50PM -0800, Sean Bruno wrote:
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> http://www.intel.com/content/dam/doc/datasheet/82574l-gbe-controller-datasheet.pdf
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> According to 7.1.11, this device does indeed have 2 queues for stuff and
> or things.  So, basic RSS would be possible in something like an Atom box.
> 
> I note that the em(4) driver intentionally disables this on
> initialization.  I'm up for some science on my new shiny, soon to be
> router box. Any reason not to default to 1 queue and allow loader.conf
> to raise it to 2?

Intel folks know better but it seems this is hartwell.

em_setup_msix() in very start says:

        /*
        ** Setup MSI/X for Hartwell: tests have shown
        ** use of two queues to be unstable, and to
        ** provide no great gain anyway, so we simply
        ** seperate the interrupts and use a single queue.
        */

Things may have changed now. I guess you can try enabling it and find out :-)

cheers,
Hiren
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