linux-kernel - Re: On thread scheduling

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Date:	Sat, 15 Sep 2007 07:39:13 +0200
From:	Matthias Kaehlcke <matthias.kaehlcke@...il.com>
To:	Heikki Orsila <shdl@...alwe.fi>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: On thread scheduling

El Sat, Sep 15, 2007 at 01:40:00AM +0300 Heikki Orsila ha dit:

> Consider a simple embedded system:
> 
> void interrupt_handler(void)
> {
> 	...
> }
> 
> int main(void)
> {
> 	...
> }
> 
> I would like to "emulate" this system with a workstation to make 
> development faster. I would create two threads, one executing the 
> main() function, and the other occasionally calling interrupt_handler(). 
> Before interrupt_handler() is called, the main() thread should be 
> stopped asynchronously.
> 
> I looked into pthreads documentation and found only pthread_kill(thread, 
> SIGTSTP) to do asynchronous stop, but then I also have to play terminal 
> tricks to avoid problems..
> 
> Is there are function to just disable scheduling of a single thread 
> without having other side-effects (such as terminal stuff)? Functions 
> like pthread_disable_scheduling(thread) and 
> pthread_enable_scheduling(thread) would be good for this..

i wonder if assigning a real time priority with
pthread_setschedparam() to the caller of your interrupt_handler()
function would solve your problem. this way the main() thread is never
scheduled when the interrupt_handler() thread is
runnable. interrupt_handler() should be as short as possible,
otherwise you risk starving of the rest of your systems processes.

-- 
Matthias Kaehlcke
Linux Application Developer
Barcelona

        Representation of the world, like the world itself, is
        the work of men; they describe it from their own point
         of view, which they  confuse with the absolute truth
                          (Simone de Beauvoir)
                                                                 .''`.
    using free software / Debian GNU/Linux | http://debian.org  : :'  :
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