[haiku-development] Re: Free irq

  • From: Sean Collins <smc.collins@xxxxxxxxxxx>
  • To: haiku-development@xxxxxxxxxxxxx
  • Date: Mon, 17 Oct 2011 00:43:43 -0400

Axel Dörfler wrote:
On 10/16/2011 05:41 PM, Michael Lotz wrote:
A rather simple optimization to the interrupt handler that could be
done however, would be to reorder the installed interrupt handler list
so that handlers who service the most interrupts end up at the top of
the list (this only applies where multiple interrupt handlers are
installed of course). This would reduce the average interrupt handling
latency by avoiding to call into the handler routine of drivers that
only receive interrupts more rarely.

I'm not sure the heuristic is sound, as while you potentially safe a few cycles by ordering them that way, devices that benefit from low latency might not issue the most interrupts. Audio drivers come to mind here, although they probably really should use MSI when possible (certainly with HDA, which should be the most common these days, anyway).

Bye,
   Axel.


Sorry to double quote, but grouping the Interrupt priority by application demand would make more sense to me.IE, if the audio subsystem is in need of the audio interface, that particular subsystem having the highest priority would make sense. IE recording of audio, similarly the same could be said about USB video streams and inputs. IE attach a webcam, and you'd want the highest priority to take precedence, not the most frequently interrupted. I'd personally want the USB to get the most attention to ensure a smooth capture. So on and so forth . Is such a thing doable ?

thats my 2 cents.

Sean

Other related posts: