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Re: CPU limit for RT audio thread?
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Re: CPU limit for RT audio thread?


  • Subject: Re: CPU limit for RT audio thread?
  • From: Jeff Moore <email@hidden>
  • Date: Tue, 11 Jan 2005 16:17:38 -0800

There are two penalties that can come about. First, the scheduler will spank a real time thread that exceeds it's constraint. The scheduler does this by degrading the priority of the thread which causes it to get pre-empted more and moer often.

The second penalty comes from the HAL itself. It knows when an IO cycle should complete. If the cycle isn't complete by a percentage of then (I think it was something like 95% in 10.3.x ), the HAL issues an overload notification and forces the IO thread to re-anchor itself and sleep for a full cycle.

On Jan 11, 2005, at 3:47 AM, Stéphane Letz wrote:

Hi,

I read that real time audio threads are "dropped" by the scheduler if they consumed too much CPU. How is this done? Is is part of the HAL or in the scheduler directly? Is there a CPU limit (like 90%) that is fixed somewhere in the system?

--

Jeff Moore
Core Audio
Apple




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References: 
 >CPU limit for RT audio thread? (From: Stéphane Letz <email@hidden>)

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