1sched_get_priority_max(2) System Calls Manual sched_get_priority_max(2)
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6 sched_get_priority_max, sched_get_priority_min - get static priority
7 range
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10 Standard C library (libc, -lc)
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13 #include <sched.h>
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15 int sched_get_priority_max(int policy);
16 int sched_get_priority_min(int policy);
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19 sched_get_priority_max() returns the maximum priority value that can be
20 used with the scheduling algorithm identified by policy.
21 sched_get_priority_min() returns the minimum priority value that can be
22 used with the scheduling algorithm identified by policy. Supported
23 policy values are SCHED_FIFO, SCHED_RR, SCHED_OTHER, SCHED_BATCH,
24 SCHED_IDLE, and SCHED_DEADLINE. Further details about these policies
25 can be found in sched(7).
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27 Processes with numerically higher priority values are scheduled before
28 processes with numerically lower priority values. Thus, the value re‐
29 turned by sched_get_priority_max() will be greater than the value re‐
30 turned by sched_get_priority_min().
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32 Linux allows the static priority range 1 to 99 for the SCHED_FIFO and
33 SCHED_RR policies, and the priority 0 for the remaining policies.
34 Scheduling priority ranges for the various policies are not alterable.
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36 The range of scheduling priorities may vary on other POSIX systems,
37 thus it is a good idea for portable applications to use a virtual pri‐
38 ority range and map it to the interval given by sched_get_prior‐
39 ity_max() and sched_get_priority_min() POSIX.1 requires a spread of at
40 least 32 between the maximum and the minimum values for SCHED_FIFO and
41 SCHED_RR.
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43 POSIX systems on which sched_get_priority_max() and sched_get_prior‐
44 ity_min() are available define _POSIX_PRIORITY_SCHEDULING in
45 <unistd.h>.
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48 On success, sched_get_priority_max() and sched_get_priority_min() re‐
49 turn the maximum/minimum priority value for the named scheduling pol‐
50 icy. On error, -1 is returned, and errno is set to indicate the error.
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53 EINVAL The argument policy does not identify a defined scheduling pol‐
54 icy.
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57 POSIX.1-2008.
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60 POSIX.1-2001.
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63 sched_getaffinity(2), sched_getparam(2), sched_getscheduler(2),
64 sched_setaffinity(2), sched_setparam(2), sched_setscheduler(2),
65 sched(7)
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69Linux man-pages 6.04 2023-03-30 sched_get_priority_max(2)