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Re: Tickless/dyntick kernel, highres timer and general time crapectomy

To: Franck Bui-Huu <vagabon.xyz@gmail.com>
Subject: Re: Tickless/dyntick kernel, highres timer and general time crapectomy
From: Ralf Baechle <ralf@linux-mips.org>
Date: Thu, 7 Jun 2007 16:48:01 +0100
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>, linux-mips@linux-mips.org
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On Thu, Jun 07, 2007 at 04:44:11PM +0200, Franck Bui-Huu wrote:

> >   No, it doesn't. Even on dyntick kernels, interrupts do happen several
> >times a second. Dynticks have nothing to do with disabling timer
> >interrupts...
> >
> 
> That's true however if your system has 2 clock devices. One is the r4k-hpt
> and the other one soemthing else with a higher rating. If you don't stop
> r4k-hpt interrupts, how does it work ?

To some degree this question is hypothetic because generally the cp0
count/compare timer will be the highest rated counter.

But even if so, the basic solution is the same - just ignore the interrupt
whenever it happens to be triggered.  Or if it isn't shared with an
active performance counter interrupt, you could even disable_irq() it.

  Ralf

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