sorry abou that,
JCN
.`'. .`'. .`'.
`.,' `.,' `.,'
frizzle@engin.umich.edu "The facts, no matter how interesting they may
.`'. .`'. .`'. be, are irrelevant!"
`.,' `.,' `.,' (A thought to get you through any crisis)
On Fri, 20 Aug 1999, Jonathan Case Nicklin wrote:
> Andr`ea,
> I benchmarked a patched version of 2.2.11 vs. the reference, and found
> some areas of concern: a slight performance degradation and a potential
> impact on real-time performance. I'm hoping you can clarify these for
> me.
>
> Using the SDM1.1 057.SDET benchmark I obtained the following.
>
> Reference 2.2.11:
> scripts throughput
> 32 6133
> 64 5599
> 96 4978
> 128 4387
> 150 4044
>
> Patched 2.2.11:
> scripts throughput
> 32 6106
> 64 5515
> 96 4928
> 128 4387
> 150 4022
>
> *these results were averaged over 20 runs and run under identical
> system states.
>
> Using make I obtained the following:
> Reference 2.2.11:
> Real: 77.82
> User: 198.26
> Sys: 20.52
>
> Patched 2.2.11:
> Real: 77.94
> User: 199.44
> Sys: 18.70
>
> As you can see, I found a (slight) performance decrease according to
> the benchmark.
>
> I agree with your conceptual view of the situation, so this is a little
> bit of a surprise. Are these the same benchmark results you came up
> with, or did I mismeasure somehow?
>
> Also, it looks to me like you removed some code in reschedule_idle
> necessary for good real-time performace, in particular, evaluating the
> preemptive_goodness of a task vs all of the tasks on all other CPU's.
> From where I sit, it looks like your implementation evaluates the
> preemptive goodness on the best_cpu only after checking avg_timeslice
> vs. cache flush time. The potential impact of this on real-time
> performance might be pretty drastic -- what do you think?
>
> Maybe it would be worthwhile to evaluate avg_timeslice vs cacheflush
> time in goodness?
>
> -JCN
>
> -
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