sched_4bsd — 4.4BSD scheduler

       While a highly robust and time-tested scheduler, sched_4bsd lacks specific knowledge of how  to  schedule
       advantageously in non-symmetric processor configurations, such as hyper-threading.

Debian                                          January 21, 2008                                   SCHED_4BSD(4)

       The  sched_4bsd  scheduler  is the traditional system scheduler, providing both high throughput and solid
       interactive response in the presence of load.

       The following sysctls are relevant to the operation of sched_4bsd:

       kern.sched.name
               This read-only sysctl reports the name of the active scheduler.

       kern.sched.quantum
               This read-write sysctl reports or sets the length of the quantum (in micro-seconds) granted to  a
               thread.

       kern.sched.ipiwakeup.enabled
               This  read-write  sysctl  sets  whether  or  not  the  scheduler will generate an inter-processor
               interrupt (IPI) to an idle CPU when a thread is woken up.  Otherwise, idle CPUs will  wait  until
               the next clock tick before looking for new work.

       kern.sched.preemption
               This  read-only  sysctl  reports  whether  or not the kernel is configured to support preemption,
               which reduces the latency to run lower priority threads on wakeup.

       Some sysctls will be available only on systems supporting SMP.

       The sched_4bsd scheduler has been present, in various forms, since the inception of BSD.

       sched_4bsd — 4.4BSD scheduler

sched_ule(4), sysctl(8)

optionsSCHED_4BSD