Re: candidate sched.h and sys/sched.h for review

[Ralf Corsepius <ralf dot corsepius at rtems dot org>]

On 03/29/2010 08:12 PM, Joel Sherrill wrote:
> Hi,
>
> Attached is a first attempt at adding sched_XXX
> prototypes to sched.h, updating sched_param to
> use the right field names for sporadic scheduler,
> and to have RTEMS and Cygwin SCHED_XXX constants
> unperturbed.
>
> I have compiled one target with this but that doesn't
> mean it is close to right.  How does it look?

Comments interspersed.

> sched.h
>
>
> /*
>   *  $Id$
>   */
>
> #ifndef_SCHED_H_
> #define_SCHED_H_
>
> #ifdef __cplusplus
> extern "C" {
> #endif
>
> #include <sys/features.h>
> #include <sys/time.h>
Why sys/time.h?

SUSV/IEEE Std 1003.1-2008 says:

<cite>
The <sched.h> header shall define the timespec structure as described in 
<time.h>.
</cite>

I don't see that this file uses any types/defines from <sys/time.h>, but 
"timespec", which is mandated to specified in <time.h>

> #include <sys/sched.h>
Please move these includes above the "#ifdef __cplusplus".

> #if defined(_POSIX_PRIORITY_SCHEDULING)
> /*
>   *  13.3.1 Set Scheduling Parameters, P1003.1b-1993, p. 252
>   */
> int sched_setparam(
>    pid_t                     pid,
>    const struct sched_param *param
> );
>
> /*
>   *  13.3.2 Set Scheduling Parameters, P1003.1b-1993, p. 253
>   */
> int sched_getparam(
>    pid_t                     pid,
>    struct sched_param       *param
> );
>
> /*
>   *  13.3.3 Set Scheduling Policy and Scheduling Parameters,
>   *         P1003.1b-1993, p. 254
>   */
> int sched_setscheduler(
>    pid_t                     pid,
>    int                       policy,
>    const struct sched_param *param
> );
>
> /*
>   *  13.3.4 Get Scheduling Policy, P1003.1b-1993, p. 256
>   */
> int sched_getscheduler(
>    pid_t                     pid
> );
>
> /*
>   *  13.3.6 Get Scheduling Parameter Limits, P1003.1b-1993, p. 258
>   */
> int sched_get_priority_max(
>    int  policy
> );
>
> int sched_get_priority_min(
>    int  policy
> );
>
> int sched_rr_get_interval(
>    pid_t             pid,
>    struct timespec  *interval
> );
> #endif /* _POSIX_PRIORITY_SCHEDULING */
>
> #if defined(_POSIX_THREADS) || defined(_POSIX_PRIORITY_SCHEDULING)
>
> /*
>   *  13.3.5 Yield Processor, P1003.1b-1993, p. 257
>   */
> int sched_yield( void );
>
> #endif /* _POSIX_THREADS or _POSIX_PRIORITY_SCHEDULING */
>
> #ifdef __cplusplus
> }
> #endif
>
> #endif /*_SCHED_H_  */
>
>
> sys_sched.h
>
>
> /*
>   *  Written by Joel Sherrill<joel@OARcorp.com>.
>   *
>   *  COPYRIGHT (c) 1989-2000.
>   *  On-Line Applications Research Corporation (OAR).
>   *
>   *  Permission to use, copy, modify, and distribute this software for any
>   *  purpose without fee is hereby granted, provided that this entire notice
>   *  is included in all copies of any software which is or includes a copy
>   *  or modification of this software.
>   *
>   *  THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR IMPLIED
>   *  WARRANTY.  IN PARTICULAR,  THE AUTHOR MAKES NO REPRESENTATION
>   *  OR WARRANTY OF ANY KIND CONCERNING THE MERCHANTABILITY OF THIS
>   *  SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR PURPOSE.
>   *
>   *  $Id: sched.h,v 1.2 2002/06/20 19:51:24 fitzsim Exp $
>   */
>
>
> #ifndef __POSIX_SYS_SCHEDULING_h
> #define __POSIX_SYS_SCHEDULING_h

I would use "_SYS_SCHED_H_".


> #ifdef __cplusplus
> extern "C" {
> #endif
>
> /* Scheduling Policies */
> /* Open Group Specifications Issue 6 */
> #if defined(__CYGWIN__)
> #define SCHED_OTHER    3
> #else
> #define SCHED_OTHER    0
> #endif
>
> #define SCHED_FIFO     1
> #define SCHED_RR       2
>
> #if defined(_POSIX_SPORADIC_SERVER)
> #define SCHED_SPORADIC 3
> #endif
>
> /* Scheduling Parameters */
> /* Open Group Specifications Issue 6 */
>
> struct sched_param {
>    int sched_priority;           /* Process execution scheduling priority */
>
> #if defined(_POSIX_SPORADIC_SERVER) || defined(_POSIX_THREAD_SPORADIC_SERVER)
>    int sched_ss_low_priority;    /* Low scheduling priority for sporadic */
>                                  /*   server */
>    struct timespec sched_ss_replenish_period;
>                                  /* Replenishment period for sporadic server */
>    struct timespec sched_ss_init_budget;
>                                 /* Initial budget for sporadic server */
>    int sched_ss_max_repl;       /* Maximum pending replenishments for */
>                                 /* sporadic server */
> #endif
> };
>
> #ifdef __cplusplus
> }
> #endif
>
> #endif
> /* end of include file */