swizzled?

Curtis Doty Curtis at GreenKey.net
Sun Apr 22 13:19:11 CDT 2007


Curtis Doty wrote:
> After updating a PE1900 to BIOS v1.3.7 it offers a new option "System
> Interrupts Assignment" with no documentation and sparse help that says,
> "when set to distributed, the interrupt routing will be swizzled to
> minimize IRQ sharing."
>
> Yet there's no googlejuice:
> http://google.com/search?q=swizzled+site:dell.com - did not match any
> documents.
>
> Would anyone @dell care to explain this term?
>   

Thanks to those who replied off-list. It appears to be another Intel
5000 Series Chipset feature designed to load-balance IRQs. The proper
google looks like this:
http://google.com/search?q=interrupt+swizzling+site:intel.com

Which leads to my real question. Why has Dell/Intel not released any
real-world benchmarks that take into consideration *all* of these combined:

    - irqbalance daemon (fiddle with cpu affinity in a smart multi-core
way) http://www.irqbalance.org/
    - latest e1000 module (now dynamically throttles interrupts under
high load)
    - I/OAT (DMA engine) http://www.intel.com/go/ioat/
    - interrupt swizzling
http://www.intel.com/design/chipsets/applnots/314337.htm

It seems all four are Intel-driven solutions incorporated into the
Xeon-based 9G PowerEdge. But none hardly mentions any of the others. :-/
And since both the e1000 module and irqbalance daemon are dynamic
solutions, while I/OAT and swizzling are handled in BIOS, do I hear the
sound of one hand clapping?

../C



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