Messages in this thread | | | Date | Tue, 6 Apr 2004 19:57:22 +0200 | From | Andrea Arcangeli <> | Subject | Re: -mmX 4G patches feedback [numbers: how much performance impact] |
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On Tue, Apr 06, 2004 at 07:24:31PM +0200, Ingo Molnar wrote: > (anyway, feel free to reproduce and post contrary results here. The onus
I will run benchmarks as soon as I'm back from vacations. You didn't post the modified benchmarks to produce any realistic load.
I will use the HINT to measure the slowdown on HZ=1000. It's an optimal benchmark simulating userspace load at various cache sizes and it's somewhat realistic.
Note also that the slowdown I expect wasn't of the order 10%, obviously, I was expecting something between 1 and 2% which would be an *huge* slowdown for any cpu bound app just for the timer irq, and I will try to reproduce it on my 4-way xeon.
Regardless, even if HZ=1000 would run 1% faster (not 0.02% slower as you measured) that changes nothing in terms of the 4:4 badness, the real badness is for apps doing more than userspace pure calculations.
> is on you. And if you think i'm upset about your approach to this whole > issue then you are damn right.)
the one upset should be the users running 30% slower with stuff like mysql just because they own a 4/8G box. There's little interest from my part to spend time on 4:4 stuff when things are so obvious (I want however to try to benchmark the HZ=1000 with the hint). - 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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