Re: Sched - graphic smoothness under load - cfs-v13 sd-0.48

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Bill Davidsen wrote:
Ray Lee wrote:
On 5/19/07, Bill Davidsen <[email protected]> wrote:
I generated a table of results from the latest glitch1 script, using an
HTML postprocessor I not *quite* ready to foist on the word. In any case
it has some numbers for frames per second, fairness of the processor
time allocated to the compute bound processes which generate a lot of
other screen activity for X, and my subjective comments on how smooth it
looked and felt.

The chart is at http://www.tmr.com/~davidsen/sched_smooth_01.html for
your viewing pleasure.

Is the S.D. columns (immediately after the average) standard
deviation? If so, you may want to rename those 'stdev', as it's a
little confusing to have S.D. stand for that and Staircase Deadline.
Further, which standard deviation is it? (The standard deviation of
the values (stdev), or the standard deviation of the mean (sdom)?)

What's intended is the stddev from the average, and perl bit me on that one. If you spell a variable wrong the same way more than once it doesn't flag it as a possible spelling error.

Note on the math, even when coded as intended, the divide of the squares of the errors is by N-1 not N. I found it both ways in online doc, but I learned it decades ago as "N-1" so I used that.
N-1 is for estimating the standard deviation from a random sample of a population (s), N is for calculating the standard deviation of a whole population (σ).

xref http://en.wikipedia.org/wiki/Standard_deviation

Yes, I am aware of the potential for Wikipedia articles to be wrong, but this article seems correct at first blush :)

Matt


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