76 lines
2.6 KiB
Groff
76 lines
2.6 KiB
Groff
'\"macro stdmacro
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.Op c p a
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.TH sched_setparam 2
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.SH NAME
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\f4sched_setparam\fP \- set the scheduling parameters of a process
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.SH C SYNOPSIS
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.nf
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\f3#include <sched.h>\f1
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.sp .6v
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\f4int sched_setparam (pid_t \f2pid\fP, const struct sched_param *\f2param\fP);\f1
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.fi
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.SH DESCRIPTION
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The \f4sched_setparam\fP system call is used to set the scheduling
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policy parameters for the process specified by \f2pid\fP. If
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\f2pid\fP is set to zero, then the scheduling parameters of the calling
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process will be affected.
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.P
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The scheduling parameters of \f2pid\fP are specified by the parameter
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structure at address \f2param\fP.
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.P
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The priority of the target process may be modified by setting
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the desired priority value in the sched_priority field of the
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\f2param\fP structure.
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.P
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Unlike IRIX 6.2 and earlier releases, processes having a higher
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numerical priority value are more important than processes having a lower
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numerical priority value. Specified priorities remain fixed, unless
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explicitly changed in the future, and are not affected by priority
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aging schemes.
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.P
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The priority range for these scheduling policies may
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be obtained via the \f4sched_get_priority_min\fP(2) and
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\f4sched_get_priority_max\fP(2) function calls.
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However, arbitrary priority values within the range should not be used.
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Developers must consider the needs of the application and how it should
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interact with the rest of the system, before selecting a real-time priority.
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For more information, see the "Real-Time Priority Band" section of
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\f4realtime\fP(5).
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.P
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The calling process must have superuser permissions to successfully execute
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\f4sched_setparam\fP.
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.P
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If the process specified by \f2pid\fP is currently executing or is in
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a runnable state, \f4sched_setparam\fP causes the process to be rescheduled
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at its new priority.
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.P
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If \f2pid\fP refers to a POSIX thread process [see \f4pthreads\fP(3P)]
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then this call retrieves the scheduling policy parameters
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that are shared by process scope threads.
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.P
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\f4sched_setparam\fP will fail if one or more of the following are true:
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.TP 15
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[EINVAL]
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One of the specified parameters at address \f2param\fP are out of range or
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scope.
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.TP
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[EPERM]
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The calling process does not have superuser permissions.
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.TP
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[ESRCH]
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The process specified by \f2pid\fP does not exist.
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.SH SEE ALSO
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realtime(5),
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sched_getparam(2),
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sched_getscheduler(2),
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sched_setscheduler(2),
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sched_yield(2),
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sched_get_priority_max(2),
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sched_get_priority_min(2),
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sched_rr_get_interval(2),
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pthreads(5)
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.SH DIAGNOSTICS
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Upon successful completion, a value of 0 is returned to the calling process.
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Otherwise, a value of -1 is returned and \f4errno\fP is set to indicate
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the error.
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