on 06/03/2008 14:55 John Baldwin said the following: > On Monday 18 February 2008 10:25:13 am Andriy Gapon wrote: >> I see that sched_4bsd has a NOP callout with a purpose of forcing a >> context switch (via softclock), so that something like a preemption >> could happen (e.g. for threads in a tight calculation loop). >> What serves the similar purpose for sched_ule? >> Or, how sched_ule deals with the issue without needing softclock's help? > > It's gone in newer versions of 4BSD in HEAD actually. ULE does it by > checking > in sched_clock() to see if the current thread has used up its quantum. If so > it sets TDF_NEEDRESCHED. >
Thank you. But where/when does actual thread switch happens? E.g. I have two userland processes that do something like "while(1);", what is the event that can switch from one to the other? -- Andriy Gapon _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "[EMAIL PROTECTED]"
