[wdmaudiodev] Pull mode versus push mode

  • From: "Jeff Pages" <jeff@xxxxxxxxxxxxxxxx>
  • To: <wdmaudiodev@xxxxxxxxxxxxx>
  • Date: Wed, 17 Nov 2010 11:25:23 +1100

We make a range of AM, FM and DAB+ radio capture cards, which create a
Windows audio capture device for each station received. Typically each card
can create up to 32 such audio capture devices.

While everyone is extolling the virtues of supporting pull mode on Windows
7, I'm wondering if, in this situation, push mode might be preferable. On a
machine fitted with an AM, FM and three DAB+ cards (a fairly typical
configuration here), if they were operating in pull mode each station would
be generating its own interrupt at a 10ms rate, creating the potential of
160 interrupts every 10ms, each queuing DPCs to trigger notification events.
Contrast this to push mode, where presumably a single system timer interrupt
causes each audio engine instance to just poll its corresponding position

Audio latency is irrelevant in this application, so my gut feeling is that
supporting pull mode would create more problems than it solves. I'd be
curious to hear what others on this list think, though.


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