Implement THREAD_PRIORITY_TIME_CRITICAL

[Andreas Mohr]

Hi,

On Fri, Mar 31, 2006 at 02:06:23PM +0100, Mike Hearn wrote:
> This patch gives me rock solid audio in Imperium Galactica 2, so now the 
> game works perfectly.
> 
> There has been discussion around this issue with respect to security in 
> the past, however, regardless of what approach is adopted this code will 
> have to be written anyway.

Ah, thanks, nice to see that it actually helps.

> +        scheduler = SCHED_FIFO;

IMHO we should really add some smart detection of SCHED_ISO kernel capability
and *much* prefer to use that one then. One really wouldn't want to hang
the box...
Not to mention that SCHED_FIFO requires root, which is an absolute PITA.

Nice To Have would be support for stuff such as SCHED_IDLEPRIO and
SCHED_BATCH...

> +    if (result == -EPERM)
> +    {
> +        static int need_warning = 1;
> +                
> +        if (need_warning)
> +        {
> +            fprintf( stderr, "\nwineserver: Failed to promote the priority of a time critical thread.\n" );
> +            fprintf( stderr, "Audio may destabilise. To fix this re-run the application as root.\n\n" );
> +            need_warning = 0;
> +        }
> +
> +        return;
> +    }

Make that
	static int already_warned; /* static: = 0! */

Since static uses 0 as default and you don't want to waste space in the
.bss(?) segment for an explicit 1 init.

Andreas Mohr

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