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

Miguel Figueiredo
2007-05-22T20:02:27Z

Bill Davidsen wrote:
> Miguel Figueiredo wrote:
>> Ray Lee wrote:
>>> On 5/20/07, Miguel Figueiredo <elmig@debianpt.org> wrote:
>>>> As I tryied myself kernels 2.6.21, 2.6.21-cfs-v13, and 2.6.21-ck2 on
>>>> the
>>>> same machine i found *very* odd those numbers you posted, so i tested
>>>> myself those kernels to see the numbers I get instead of talking about
>>>> the usage of kernel xpto feels like.
>>>>
>>>> I did run glxgears with kernels 2.6.21, 2.6.21-cfs-v13 and 2.6.21-ck2
>>>> inside Debian's GNOME environment. The hardware is an AMD Sempron64 3.0
>>>> GHz, 1 GB RAM, Nvidia 6800XT.
>>>> Average and standard deviation from the gathered data:
>>>>
>>>> * 2.6.21: average = 11251.1; stdev = 0.172
>>>> * 2.6.21-cfs-v13: average = 11242.8; stdev = 0.033
>>>> * 2.6.21-ck2: average = 11257.8; stdev = 0.067
>>>>
>>>> Keep in mind those numbers don't mean anything we all know glxgears is
>>>> not a benchmark, their purpose is only to be used as comparison under
>>>> the same conditions.
>>>
>>> Uhm, then why are you trying to use them to compare against Bill's
>>> numbers? You two have completely different hardware setups, and this
>>> is a test that is dependent upon hardware. Stated differently, this is
>>> a worthless comparison between your results and his as you are
>>> changing multiple variables at the same time. (At minimum: the
>>> scheduler, cpu, and video card.)
>>
>> The only thing i want to see it's the difference between the behaviour
>> of the different schedulers on the same test setup. In my test -ck2
>> was a bit better, not 200% worse as in Bill's measurements. I don't
>> compare absolute values on different test setups.
>>
> Since I didn't test ck2 I'm sure your numbers are unique, I only tested
> the sd-0.48 patch set. I have the ck2 patch, just haven't tried it
> yet... But since there are a lot of other things in it, I'm unsure how
> it relates to what I was testing.
>>>
>>>> One odd thing i noticed, with 2.6.21-cfs-v13 the gnome's time applet in
>>>> the bar skipped some minutes (e.g. 16:23 -> 16:25) several times.
>>>>
>>>> The data is available on:
>>>> http://www.debianPT.org/~elmig/pool/kernel/20070520/
>>>>
>>>>
>>>> How did you get your data? I am affraid your data it's wrong,
>>>> there's no
>>>> such big difference between the schedulers...
>>>
>>> It doesn't look like you were running his glitch1 script which starts
>>> several in glxgears parallel. Were you, or were you just running one?
>>
>> No i'm not, i'm running only one instance of glxgears inside the
>> GNOME's environment.
>>
> If you test the same conditions as I did let me know your results.
>

Hi Bill,

if i've understood correctly the script runs glxgears for 43 seconds and
in that time generates random numbers in a random number of times
(processes, fork and forget), is that it?

You find the data, for 2.6.21-{cfs-v13, ck2} in
http://www.debianpt.org/~elmig/pool/kernel/20070522/

Here's the funny part...

Lets call:

a) to "random number of processes run while glxgears is running",
gl_fairloops file

b) to "generated frames while running a burst of processes" aka "massive
and uknown amount of operations in one process", gl_gears file

kernel 2.6.21-cfs-v13 2.6.21-ck2
a) 194464 254669
b) 54159 124

--

Com os melhores cumprimentos/Best regards,

Miguel Figueiredo