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

From: Ray Lee
Date: Sun May 20 2007 - 02:30:29 EST


On 5/19/07, Michael Gerdau <mgd@xxxxxxxxxxxx> wrote:
> Okay, here's a bonus, http://www.tmr.com/~davidsen/sched_smooth_02.html
> not only has the right values, the labels are changed, and I included
> more data points from the fc6 recent kernel and the 2.6.21.1 kernel with
> the mainline scheduler.
>
> The nice thing about this test and the IPC test I posted recently is
> that they are reasonable stable on the same hardware, so even if someone
> argues about what they show, they show the same thing each time and can
> therefore be used to compare changes.

I'm not sure I follow you here. The difference between 2.6.21 and 2.6.21.1
are two simple (as in involving little code) changes to ip4 and ip6 net
and I'm not even sure that code is used at all in your tests.
[Read: IMO the 2.6.21 and 2.6.21.1 figures are for identical cases].

Assuming the above is correct then IMO the variance between the two
"dublicated" lines (cfs-v13 and sd048) is such that I would not have
written "that they are reasonable stable on the same hardware".

I don't want to say the values aren't useful. I simply think there is
a high noiselevel.

The noise is reflected in the standard deviation he has on those rows.
The average +- stdev of one overlaps the average +- stdev of the
other, which shows that the test *is* stable, where stable (as always)
is defined to some accuracy.
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