sched_4bsd(4) [freebsd man page]
SCHED_4BSD(4) BSD Kernel Interfaces Manual SCHED_4BSD(4) NAME
sched_4bsd -- 4.4BSD scheduler SYNOPSIS
options SCHED_4BSD DESCRIPTION
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. SEE ALSO
sched_ule(4), sysctl(8) HISTORY
The sched_4bsd scheduler has been present, in various forms, since the inception of BSD. BUGS
While a highly robust and time-tested scheduler, sched_4bsd lacks specific knowledge of how to schedule advantageously in non-symmetric pro- cessor configurations, such as hyper-threading. BSD
January 21, 2008 BSD
Check Out this Related Man Page
tapset::scheduler(3stap) tapset::scheduler(3stap) NAME
tapset::scheduler - systemtap scheduler tapset DESCRIPTION
scheduler.cpu_off Process is about to stop running on a cpu See probe::scheduler.cpu_off(3stap) for details. scheduler.cpu_on Process is beginning execution on a cpu See probe::scheduler.cpu_on(3stap) for details. scheduler.tick Schedulers internal tick, a processes timeslice accounting is updated See probe::scheduler.tick(3stap) for details. scheduler.balance A cpu attempting to find more work. See probe::scheduler.balance(3stap) for details. scheduler.ctxswitch A context switch is occuring. See probe::scheduler.ctxswitch(3stap) for details. scheduler.kthread_stop A thread created by kthread_create is being stopped See probe::scheduler.kthread_stop(3stap) for details. scheduler.kthread_stop.return A kthread is stopped and gets the return value See probe::scheduler.kthread_stop.return(3stap) for details. scheduler.wait_task Waiting on a task to unschedule (become inactive) See probe::scheduler.wait_task(3stap) for details. scheduler.wakeup Task is woken up See probe::scheduler.wakeup(3stap) for details. scheduler.wakeup_new Newly created task is woken up for the first time See probe::scheduler.wakeup_new(3stap) for details. scheduler.migrate Task migrating across cpus See probe::scheduler.migrate(3stap) for details. scheduler.process_free Scheduler freeing a data structure for a process See probe::scheduler.process_free(3stap) for details. scheduler.process_exit Process exiting See probe::scheduler.process_exit(3stap) for details. scheduler.process_wait Scheduler starting to wait on a process See probe::scheduler.process_wait(3stap) for details. scheduler.process_fork Process forked See probe::scheduler.process_fork(3stap) for details. scheduler.signal_send Sending a signal See probe::scheduler.signal_send(3stap) for details. SEE ALSO
probe::scheduler.cpu_off(3stap), probe::scheduler.cpu_on(3stap), probe::scheduler.tick(3stap), probe::scheduler.balance(3stap), probe::scheduler.ctxswitch(3stap), probe::scheduler.kthread_stop(3stap), probe::scheduler.kthread_stop.return(3stap), probe::scheduler.wait_task(3stap), probe::scheduler.wakeup(3stap), probe::scheduler.wakeup_new(3stap), probe::scheduler.migrate(3stap), probe::scheduler.process_free(3stap), probe::scheduler.process_exit(3stap), probe::scheduler.process_wait(3stap), probe::scheduler.process_fork(3stap), probe::scheduler.signal_send(3stap), stap(1), stapprobes(3stap) IBM
--- tapset::scheduler(3stap)