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   systemd.exec    ( 5 )

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SCHEDULING

Nice= Sets the default nice level (scheduling priority) for executed processes. Takes an integer between -20 (highest priority) and 19 (lowest priority). In case of resource contention, smaller values mean more resources will be made available to the unit's processes, larger values mean less resources will be made available. See setpriority(2) for details.

CPUSchedulingPolicy= Sets the CPU scheduling policy for executed processes. Takes one of other, batch, idle, fifo or rr. See sched_setscheduler(2) for details.

CPUSchedulingPriority= Sets the CPU scheduling priority for executed processes. The available priority range depends on the selected CPU scheduling policy (see above). For real-time scheduling policies an integer between 1 (lowest priority) and 99 (highest priority) can be used. In case of CPU resource contention, smaller values mean less CPU time is made available to the service, larger values mean more. See sched_setscheduler(2) for details.

CPUSchedulingResetOnFork= Takes a boolean argument. If true, elevated CPU scheduling priorities and policies will be reset when the executed processes call fork(2), and can hence not leak into child processes. See sched_setscheduler(2) for details. Defaults to false.

CPUAffinity= Controls the CPU affinity of the executed processes. Takes a list of CPU indices or ranges separated by either whitespace or commas. Alternatively, takes a special "numa" value in which case systemd automatically derives allowed CPU range based on the value of NUMAMask= option. CPU ranges are specified by the lower and upper CPU indices separated by a dash. This option may be specified more than once, in which case the specified CPU affinity masks are merged. If the empty string is assigned, the mask is reset, all assignments prior to this will have no effect. See sched_setaffinity(2) for details.

NUMAPolicy= Controls the NUMA memory policy of the executed processes. Takes a policy type, one of: default, preferred, bind, interleave and local. A list of NUMA nodes that should be associated with the policy must be specified in NUMAMask=. For more details on each policy please see, set_mempolicy(2). For overall overview of NUMA support in Linux see, numa(7).

NUMAMask= Controls the NUMA node list which will be applied alongside with selected NUMA policy. Takes a list of NUMA nodes and has the same syntax as a list of CPUs for CPUAffinity= option or special "all" value which will include all available NUMA nodes in the mask. Note that the list of NUMA nodes is not required for default and local policies and for preferred policy we expect a single NUMA node.

IOSchedulingClass= Sets the I/O scheduling class for executed processes. Takes an integer between 0 and 3 or one of the strings none, realtime, best-effort or idle. If the empty string is assigned to this option, all prior assignments to both IOSchedulingClass= and IOSchedulingPriority= have no effect. See ioprio_set(2) for details.

IOSchedulingPriority= Sets the I/O scheduling priority for executed processes. Takes an integer between 0 (highest priority) and 7 (lowest priority). In case of I/O contention, smaller values mean more I/O bandwidth is made available to the unit's processes, larger values mean less bandwidth. The available priorities depend on the selected I/O scheduling class (see above). If the empty string is assigned to this option, all prior assignments to both IOSchedulingClass= and IOSchedulingPriority= have no effect. See ioprio_set(2) for details.