Re: [REPORT] cfs-v4 vs sd-0.44

William Lee Irwin III
2007-04-22T08:13:02Z

On Sat, Apr 21, 2007 at 02:17:02PM -0400, Gene Heskett wrote:
> CFS-v4 is quite smooth in terms of the users experience but after prolonged
> observations approaching 24 hours, it appears to choke the cpu hog off a bit
> even when the system has nothing else to do. My amanda runs went from 1 to
> 1.5 hours depending on how much time it took gzip to handle the amount of
> data tar handed it, up to about 165m & change, or nearly 3 hours pretty
> consistently over 5 runs.

Welcome to infinite history. I'm not surprised, apart from the time
scale of anomalies being much larger than I anticipated.

On Sat, Apr 21, 2007 at 02:17:02PM -0400, Gene Heskett wrote:
> sd-0.44 so far seems to be handling the same load (theres a backup running
> right now) fairly well also, and possibly theres a bit more snap to the
> system now. A switch to screen 1 from this screen 8, and the loading of that
> screen image, which is the Cassini shot of saturn from the backside, the one
> showing that teeny dot to the left of Saturn that is actually us, took 10
> seconds with the stock 2.6.21-rc7, 3 seconds with the best of Ingo's patches,
> and now with Con's latest, is 1 second flat. Another screen however is 4
> seconds, so maybe that first scren had been looked at since I rebooted.
> However, amanda is still getting estimates so gzip hasn't put a tiewrap
> around the kernels neck just yet.

Not sure what you mean by gzip putting a tiewrap around the kernel's neck.
Could you clarify?

On Sat, Apr 21, 2007 at 02:17:02PM -0400, Gene Heskett wrote:
> Some minutes later, gzip is smunching /usr/src, and the machine doesn't even
> know its running as sd-0.44 isn't giving gzip more than 75% to gzip, and
> probably averaging less than 50%. And it scared me a bit as it started out at
> not over 5% for the first minute or so. Running in the 70's now according to
> gkrellm, with an occasional blip to 95%. And the machine generally feels
> good.

I wonder what's behind that sort of initial and steady-state behavior.

On Sat, Apr 21, 2007 at 02:17:02PM -0400, Gene Heskett wrote:
> I had previously given CFS-v4 a 95 score but that was before I saw
> the general slowdown, and I believe my first impression of this one
> is also a 95. This on a scale of the best one of the earlier CFS
> patches being 100, and stock 2.6.21-rc7 gets a 0.0. This scheduler
> seems to be giving gzip ever more cpu as time progresses, and the cpu
> is warming up quite nicely, from about 132F idling to 149.9F now.
> And my keyboard is still alive and well.
> Generally speaking, Con, I believe this one is also a keeper. And we'll see
> how long a backup run takes.

Pardon my saying so but you appear to be describing anomalous behavior
in terms of "scheduler warmups."