Messages in this thread | | | Subject | Re: Delayed interrupt work, thread pools | From | Benjamin Herrenschmidt <> | Date | Wed, 02 Jul 2008 12:38:52 +1000 |
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On Tue, 2008-07-01 at 20:39 -0500, Dean Nelson wrote: > As Robin, mentioned XPC manages a pool of kthreads that can (for performance > reasons) be quickly awakened by an interrupt handler and that are able to > block for indefinite periods of time. > > In drivers/misc/sgi-xp/xpc_main.c you'll find a rather simplistic attempt > at maintaining this pool of kthreads. > > The kthreads are activated by calling xpc_activate_kthreads(). Either idle > kthreads are awakened or new kthreads are created if a sufficent number of > idle kthreads are not available. > > Once finished with current 'work' a kthread waits for new work by calling > wait_event_interruptible_exclusive(). (The call is found in > xpc_kthread_waitmsgs().) > > The number of idle kthreads is limited as is the total number of kthreads > allowed to exist concurrently. > > It's certainly not optimal in the way it maintains the number of kthreads > in the pool over time, but I've not had the time to spare to make it better. > > I'd love it if a general mechanism were provided so that XPC could get out > of maintaining its own pool.
Thanks. That makes one existing in-tree user and a one likely WIP user, probably enough to move forward :-)
I'll look at your implementation and discuss internally see what our specific needs in term of number of threads etc... look like.
I might come up with something simple first (ie, generalizing your current implementation for example) and then look at some smarter management of the thread pools.
Cheers, Ben.
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