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Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows ?

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MitchAlsup <MitchAlsup@aol.com> wrote:
> x86 enters an uninteruptable state at the transfer of control to the
> interupt handler. So until the interrupt handler (or OS) reenables the
> interrupt (or you return from interrupt) it will not 'take' another one.

Note that if you have a preemptable kernel, page faults also have to be set
up to be an "interrupt" exception with this auto-masking.  Otherwise you can
take a hardware interrupt in the window from the exception until you read
CR2, have that interrupt dispatch a higher priority task (or otherwise cause
a page fault), and find CR2's value changed by the time you switch back to
the preempted page fault code path.

But Mitch is quite correct, the tendency is to do too much in the interrupt
handler path.  RSX-11, for instance, had solid guidelines on how much time to
spend in there, and also excellent facilities for arranging further
processing out of the front-line interrupt handler.

-- 
Andy Valencia
Home page: http://www.vsta.org/andy/
To contact me: http://www.vsta.org/contact/andy.html

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Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? MitchAlsup <MitchAlsup@aol.com> - 2011-07-01 07:45 -0700
  Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? vandys@vsta.org - 2011-07-01 17:03 +0000
  Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? jsavard@excxn.aNOSPAMb.cdn.invalid (John Savard) - 2011-07-01 20:10 +0000
    Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? Terje Mathisen <"terje.mathisen at tmsw.no"> - 2011-07-02 09:29 +0200
      Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? Andrew Reilly <areilly---@bigpond.net.au> - 2011-07-02 13:37 +0000
  Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-07-03 09:52 +0200
    Re: Do x86 or arm processors have "interrupt overload protection" or maybe windows  ? "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-07-03 09:58 +0200

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