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

Ray Lee
2007-05-20T06:30:27Z

On 5/19/07, Michael Gerdau <mgd@technosis.de> 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.