Scheduler time slice modification with the schedo command

The length of the scheduler time slice can be modified with the schedo command. To change the time slice, use the schedo -o timeslice=value option.

The value of -t is the number of ticks for the time slice and only SCHED_RR threads will use the nondefault time slice value (see Scheduling policy for threads for a description of fixed priority threads).

Changing the time slice takes effect instantly and does not require a reboot.

A thread running with SCHED_OTHER or SCHED_RR scheduling policy can use the CPU for up to a full time slice (the default time slice being 1 clock tick), a clock tick being 10 ms.

In some situations, too much context switching is occurring and the overhead of dispatching threads can be more costly than allowing these threads to run for a longer time slice. In these cases, increasing the time slice might have a positive impact on the performance of fixed-priority threads. Use the vmstat and sar commands for determining the number of context switches per second.

In an environment in which the length of the time slice has been increased, some applications might not need or should not have the full time slice. These applications can give up the processor explicitly with the yield() system call (as can programs in an unmodified environment). After a yield() call, the calling thread is moved to the end of the dispatch queue for its priority level.