[Wiltshire] Linux 2.6.28, ondemand governor and nice 19 processes

[Richard Reynolds]

Have you rolled your own kernel or used a Gentoo one? It could be that
the default options have changed. Fire up your kernel config and check
the settings, sounds like it isn't kicking in at all.

It may also be the case that your CPU is an unlucky one this update as
there are various instances where the governor code doesn't work due
to CPUs own governors etc. It may well be fixed in the next
incarnation

2009/2/22 Robert <RobertCL at iname.com>:
> Hello,
>
> I'm hoping someone will be able to help with a problem I've been
> experiencing ever since I upgraded to 2.6.28
>
> I run Boinc (seti at home, etc) as a background process on my quad core
> server at a nice level of 19 and I'm using the ondemand CPU governor.
>
> Before upgrading to 2.6.28 processes running at nice 19 didn't cause the
> CPU frequency to step up, so it ran at it's lowest clock speed, which
> was perfect because it "saved" power and kept temperatures down.
>
> Since upgrading to 2.6.28, however it seems that this is not the case.
> So running Boinc causes all my CPU's to run at full clock speed all of
> the time, which I don't want - not only because it generates more heat
> and uses more power, but it also seems to interfere with processes
> running at higher nice levels, which I never really had a problem with
> before.
>
> I've tried everything I can think of to get back to the previous
> behaviour, but I'm at a bit of a loss what to search for or where to ask
> about this!  Some (useful?) output below.
>
> As a workaround, I've currently limited the CPU time in the Boinc
> manager to only use 50% of the available CPU's which means that 2 cores
> run at 2.4GHz and two run at 1.6GHz, but this doesn't seem to be the
> right solution and still causes the box to run hotter than if both idle
> at 1.6GHz all the time
>
> Any suggestions appreciated!
> Robert.
>
>
> robert at quad ~ $ cat /proc/version
> Linux version 2.6.28.4 (root at quad) (gcc version 4.1.2 (Gentoo 4.1.2
> p1.1)) #6 SMP PREEMPT Sun Feb 8 12:42:20 GMT 2009
>
> robert at quad ~ $ cat /sys/devices/system/cpu/cpu?/cpufreq/scaling_governor
> ondemand
> ondemand
> ondemand
> ondemand
>
> robert at quad ~ $ cat
> /sys/devices/system/cpu/cpu?/cpufreq/ondemand/ignore_nice_load
> 1
> 1
> 1
> 1
>
> robert at quad ~ $ cat /proc/cpuinfo |grep MHz
> cpu MHz         : 1600.000
> cpu MHz         : 2400.000
> cpu MHz         : 1600.000
> cpu MHz         : 2400.000
>
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