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34 .Cd "options SCHED_4BSD"
37 is the default system scheduler, providing both high throughput and solid
38 interactive response in the presence of load.
40 The following sysctls are relevant to the operation of
42 .Bl -tag -width indent
44 This read-only sysctl reports the name of the active scheduler.
45 .It kern.sched.quantum
46 This read-write sysctl reports or sets the length of the quantum (in
47 micro-seconds) granted to a thread.
48 .It kern.sched.ipiwakeup.enabled
49 This read-write sysctl sets whether or not the scheduler will generate an
50 inter-processor interrupt (IPI) to an idle CPU when a thread is woken up.
51 Otherwise, idle CPUs will wait until the next clock tick before looking for
53 .It kern.sched.preemption
54 This read-only sysctl reports whether or not the kernel is configured to
55 support preemption, which reduces the latency to run lower priority threads
59 Some sysctls will be available only on systems supporting SMP.
66 scheduler has been present, in various forms, since the inception of
69 While a highly robust and time-tested scheduler,
71 lacks specific knowledge of how to schedule advantageously in non-symmetric
72 processor configurations, such as hyper-threading.