sched.h(3head) [opensolaris man page]
sched.h(3HEAD) Headers sched.h(3HEAD) NAME
sched.h, sched - execution scheduling SYNOPSIS
#include <sched.h> DESCRIPTION
The <sched.h> header defines the sched_param structure, which contains the scheduling parameters required for implementation of each sup- ported scheduling policy. This structure contains the following member: int sched_priority process execution scheduling priority Each process is controlled by an associated scheduling policy and priority. Associated with each policy is a priority range. Each policy definition specifies the minimum priority range for that policy. The priority ranges for each policy may overlap the priority ranges of other policies. The scheduling policies are indicated by the values of the following symbolic constants: SCHED_OTHER Processes are scheduled according to the traditional Time-Sharing Class (TS) policy as described in priocntl(2). SCHED_FIFO Processes are scheduled in the Real-Time (RT) scheduling class, according to the First-In-First-Out (FIFO) policy. Pro- cesses scheduled to this policy, if not preempted by a higher priority or interrupted by a signal, will proceed until com- pletion. SCHED_RR Processes are scheduled in the Real-Time (RT) scheduling class, according to the Round-Robin (RR) policy. Processes sched- uled to this policy, if not preempted by a higher priority or interrupted by a signal, will execute for a time period, returned by sched_rr_get_interval(3C) or by the system. SCHED_IA Processes are scheduled according to the Inter-Active Class (IA) policy as described in priocntl(2). SCHED_FSS Processes are scheduled according to the Fair-Share Class (FSS) policy as described in priocntl(2). SCHED_FX Processes are scheduled according to the Fixed-Priority Class (FX) policy as described in priocntl(2). The values of these constants are distinct. Inclusion of the <sched.h> header will make visible symbols defined in the header <time.h>. SEE ALSO
priocntl(2), sched_get_priority_max(3C), sched_get_priority_min(3C), sched_rr_get_interval(3C), time.h(3HEAD) SunOS 5.11 1 Apr 2008 sched.h(3HEAD)
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GET_PRIORITY_MAX(2) Linux Programmer's Manual GET_PRIORITY_MAX(2) NAME
sched_get_priority_max, sched_get_priority_min - get static priority range SYNOPSIS
#include <sched.h> int sched_get_priority_max(int policy); int sched_get_priority_min(int policy); DESCRIPTION
sched_get_priority_max returns the maximum priority value that can be used with the scheduling algorithm identified by policy. sched_get_priority_min returns the minimum priority value that can be used with the scheduling algorithm identified by policy. Supported policy values are SCHED_FIFO, SCHED_RR, and SCHED_OTHER. Processes with numerically higher priority values are scheduled before processes with numerically lower priority values. Thus, the value returned by sched_get_priority_max will be greater than the value returned by sched_get_priority_min. Linux allows the static priority value range 1 to 99 for SCHED_FIFO and SCHED_RR and the priority 0 for SCHED_OTHER. Scheduling priority ranges for the various policies are not alterable. The range of scheduling priorities may vary on other POSIX systems, thus it is a good idea for portable applications to use a virtual pri- ority range and map it to the interval given by sched_get_priority_max and sched_get_priority_min. POSIX.1b requires a spread of at least 32 between the maximum and the minimum values for SCHED_FIFO and SCHED_RR. POSIX systems on which sched_get_priority_max and sched_get_priority_min are available define _POSIX_PRIORITY_SCHEDULING in <unistd.h>. RETURN VALUE
On success, sched_get_priority_max and sched_get_priority_min return the maximum/minimum priority value for the named scheduling policy. On error, -1 is returned, errno is set appropriately. ERRORS
EINVAL The parameter policy does not identify a defined scheduling policy. CONFORMING TO
POSIX.1b (formerly POSIX.4) SEE ALSO
sched_setscheduler(2), sched_getscheduler(2), sched_setparam(2), sched_getparam(2) sched_setscheduler(2) has a description of the Linux scheduling scheme. Programming for the real world - POSIX.4 by Bill O. Gallmeister, O'Reilly & Associates, Inc., ISBN 1-56592-074-0 IEEE Std 1003.1b-1993 (POSIX.1b standard) ISO/IEC 9945-1:1996 Linux 1.3.81 1996-04-10 GET_PRIORITY_MAX(2)