2008/039 [POSIX scheduling interfaces]

[Joseph Kowalski]

Glenn Skinner wrote:
>     Date: Thu, 17 Jan 2008 12:25:22 -0800 (PST)
>     From: "Roger A. Faulkner" <Roger.Faulkner at sun.com>
>     Subject: Re: 2008/039 [POSIX scheduling interfaces]
>
>     > Date: Thu, 17 Jan 2008 10:25:27 -0800 (PST)
>     > From: Glenn Skinner <glenn.skinner at sun.com>
>     > Subject: Re: 2008/039 [POSIX scheduling interfaces]
>
>     > [various questions concerning stability and compatibility]
>
>     ...
>     Yes, but it rectifies a standards violation.  The standards
>     interfaces require priorities, low to high, to reflect real
>     scheduling priorities, low to high.
>
>     The old behavior of returning nice values (inverted at that) was
>     just a badly mistaken bug.
>
>     ...
>     Well, my understanding of the scheduler class interfaces in the
>     kernel is that it is all uncommitted, unstable, whatever.  Not
>     even as high as 'evolving'.
>
>     The priocntl() interfaces are a bit higher, but the PC_GETPRIRANGE
>     subcommand in particular is consolidation private:
>
>     From <sys/priocntl.h>:
>
>     #define PC_GETPRIRANGE  5       /* Get global priority range for a class */
>                                     /* posix.4 scheduling, not for general use */
>
>     and my addition to this file should also be consolidation private:
>
>     #define PC_DOPRIO       11      /* Set or get priority, not for general use */
>
>     I'm not deleting any visible symbols.  The THREAD_MIN_PRIORITY and
>     THREAD_MAX_PRIORITY were never visible as themselves.  Only
>     thr_setprio() and thr_getprio() ever documented their ranges.
>
>     What will break?  It's hard to say.  Something that actually
>     believed the old stuff worked, I guess.  (It never did.)
>
>     Certainly, third-party scheduling classes will break.
>     But I couldn't find any using Google.
>
> Ok, that's what I wanted to know and I'm satisfied with the answers.
> Thanks!
>
> 		-- Glenn
>   
After raf's posting, I want to check and clarify the commitments, which 
will take
me a day or so.  I agree that what raf is doing is the right thing (I 
remember some
of these issues), so at most this will result in a few more words in 
raf's proposal.

- jek3