Re: [Discuss-gnuradio] End-to-end delay question

[Eric Blossom]

On Wed, May 23, 2007 at 10:30:32AM -0400, Michael Dickens wrote:
> On May 22, 2007, at 11:46 PM, Eric Blossom wrote:
> >pthread_attr_setschedpolicy is not the same thing as
> >sched_setscheduler.  It's for setting up the attribute that is passed
> >pthread_create.
> 
> Touché.  Thanks for pointing that out ... should have been  
> "pthread_setschedparam()" instead.  This routine is, if I'm reading  
> the MAN pages correctly, an exact parallel to "sched_setscheduler()",  
> but in pthread terms.  Here's the basic code:

That makes more sense.

> Interestingly, at least on OSX 10.4.9, all policies have a (min,max)  
> priority of (15,47), and the default for any process is the mid-point  
> (31).  Thus for OSX, "real time" priority needs to be closer to the  
> MAX than the mid-point.  The default policy is "Other" (1), whatever  
> that is.

They may be interpreted in different domains.  That is, one range for
each policy.  I suspect that this is spelled out somewhere in the OS/X
developer docs.

SCHED_OTHER is the normal "time sharing" algorithm.  The details will
vary by implementation, but typically non-interactive or CPU bound
processes are penalized relative to interactive processes.

> But, again, for some reason 'configure' isn't registering that  
> pthreads are available on OSX 10.4 ... which they clearly are. - MLD

Eric