Messages in this thread | | | Date | Mon, 4 Jun 2001 16:08:37 -0700 | From | Mike Kravetz <> | Subject | reschedule_idle changes in ac kernels |
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I just noticed the changes to reschedule_idle() in the 2.4.5-ac kernel. I suspect these are the changes made for:
o Fix off by one on real time pre-emption in scheduler
I'm curious if anyone has ran any benchmarks before and after applying this fix.
The reason I ask is that during the development of my multi-queue scheduler, I 'accidently' changed reschedule_idle code to trigger a preemption if preemption_goodness() was greater than 0, as opposed to greater than 1. I believe this is the same change made to the ac kernel. After this change, we saw a noticeable drop in performance for some benchmarks.
The drop in performance I saw could have been the result of a combination of the change, and my multi-queue scheduler. However, in any case aren't we now going to trigger more preemptions?
I understand that we need to make the fig to get the realtime semantics correct, but we also need to be aware of performance in the non-realtime case.
-- Mike Kravetz mkravetz@sequent.com IBM Linux Technology Center - 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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