Re: [cpufreq] ondemand works, conservative doesn't

[Sven Köhler <skoehler@upb.de>]

>> currently, i'm using the ondemand governor. My CPU supports the
>> frequencies 800, 1800 and 2000 MHz (AMD Athlon64 Desktop with
>> Cool&Quiet). The simple bash commands
>>
>  
> In my case, I have a Pentium M 1.8ghz 400 FSB. In powersave, it goes to
> 1.19ghz, in conservative, it goes to 1.20GHZ and of course performance
> goes to 1.8ghz if plugged.
> 
> Conservative works well here, and so far, lt moved slowly from
> frequencies, 1.2 then in 5 seconds 1.4, 2 seconds 1.8. Then it took the
> CPU like 10 seconds to move back from 1.8ghz to 1.2..

Yes. Pentium M CPUs offer frequencies is 200MHz steps. And I was pretty
sure, that the conservative govenor works in that case.

> Mine did reach the full cpu in a moment, yours looks like it not going
> over 2.0ghz. Maybe is not needing that much CPU?

Running an "while true; do true; done" will result in process named
"bash" that uses 100% of the cpu. The problem i see is, that the
conservative govenor never considers to switch from 800MHz to 1800MHz
because it's a 1000MHz jump! (i'd consider that as a bug, since the
govenor is non-functional in such an environment)

> If it only supports 800, 1800 and 2000 MHz, then it will only jump to
> those frequencies. I use the CPU Frequency Scaling Monitor included in
> gnome to switch between these options a lot. Maybe you could play with
> this a bit more and see how it behaves. It does look like it might need
> more frequencies, but you would need to check what does you CPU support.

I would be very glad, if the conservative-govenor would switch to the
three frequencies i listet. The problem is: it doesn't.

AFAIK, AMD Desktop CPUs really support 3 frequencies only :-(
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/