Messages in this thread | | | From | Peter Desnoyers <> | Subject | Re: kernel thread support - LWP's | Date | Thu, 15 Jul 1999 14:04:13 -0400 (EDT) |
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Donald Sharp wrote: > > I have never understood this arguement. With LWP's you have to spend > time in 2 schedulers: The kernel's and the Thread libraries. I guess > they might be able to claim that the thread libraries scheduler is much > much faster than the kernel's scheduler, so you end up with a bonus.
Splitting an N-job scheduling task into an M-job low-level scheduling tasks and a single N/M-job high-level scheduling task is a win. In theory.
In practice it depends. There's a list traversal in schedule() that would speed up if you have a whole bunch of threads and you split the scheduling into two levels, but it's probably going to take a lot of runnable tasks before this loop dominates the other overhead, and at that point a bit of overhead in schedule() is probably the least of your worries.
-- ............................................................................ Peter Desnoyers 162 Pleasant St. (617) 661-1979 pjd@fred.cambridge.ma.us Cambridge, Mass. 02139 (978) 461-0402 (work) pjd@giga-net.com
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