Messages in this thread | | | From | Mark_H_Johnson@raytheon ... | Subject | Re: [patch] Real-Time Preemption, -RT-2.6.10-rc1-mm3-V0.7.23 | Date | Wed, 10 Nov 2004 11:35:18 -0600 |
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>you have to build another kernel for them. irqs-off and preempt-off >timing can be mixed freely (and both can be enabled in the same kernel), >but wakeup timing deserves its own .config space and since it's not >mixable with the other two methods i didnt see much point in enabling >all 3 at once with strange dependencies between them. Is this a big >issue? Normally i think the wakeup timing is more than enough to get a >feel of latencies, and if something specific is suspected the other ones >can be turned on.
Just that it takes an hour or so to rebuild the kernel plus the disk storage to keep two kernels instead of one.
The wakeup latencies I am seeing are all quite small, but the overhead I am seeing at the application level have been quite high. Only 40 wakeup latencies > 50 usec in a half hour of testing. I guess I'll build a .24 without wakeup timing to see what kind of problems I'm having. I can send you the wakeup timing traces if you are interested but they are all really short (< 100 usec) or appear to indicate a hardware contention problem (one step at 100 usec or so).
--Mark
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