Messages in this thread | | | Date | Wed, 18 Jun 2003 15:29:00 -0700 | From | george anzinger <> | Subject | Re: O(1) scheduler seems to lock up on sched_FIFO and sched_RR tasks |
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Joe Korty wrote: > On Wed, Jun 18, 2003 at 09:47:24AM -0700, george anzinger wrote: > >>It seems that once a SCHED_FIFO or SCHED_RR tasks gets control it does >>not yield to other tasks of higher priority. >> >>Attached is a test program (busyloop) that just loops doing >>gettimeofday() for the requested time and a little utility (rt) to run >>programs at real time priorities. >> >>Here is an annotated example of the problem: >> >>First, become root then: >> >>>rt 90 bash <-- run bash at priority 90 SCHED_RR >>>rt -f 30 busyloop 10 & <-- busyloop 10 at priority 30 SCHED_FIFO >> >>At this point the bash at priority 90 should be available, but is not. >> When the 10 second busyloop completes, bash returns. > > > > Hi George, > When I boost the priority of each of the per-cpu 'events/%d' daemon to > 96, the problem goes away.
Seems like your saying that the events workqueues are involved in the scheduler in some ugly way. Certainly not what your average rt programmer would expect :( What is going on here?
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-- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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