[Slackbuilds-users] atlas3.10.3 build fails due to throttling

[B Watson]

On 2/25/17, Daniil Bratashov <dn2010 at gmail.com> wrote:
> citing slackbuild instructions:
> As with Slackware 14.2 you can run /etc/rc.d/rc.cpufreq as root with
> "performance" as command line
> argument.
>
> If you'll still have trottling issues (I had with Haswell), you can
> add --cripple-atlas-performance to ./configure arguments inside the
> slackbuild.

This is fresh in my mind, I just had to do this on my laptop yesterday.

'performance' still allows the CPU to be throttled, even though the
comments in rc.cpufreq imply that it doesn't. I ended up using the
cpufreq-set command in rc.local.

It would really be nice if there were a simple option to cpufreq-set
that means "disable throttling, run at max speed all the time", but
there isn't one: you can do it, but you have to include the frequency
on the command line.

Also, the -r (all hardware-related CPUs) switch seems to be broken. So
you have to repeat the command for each core. So my rc.local has:

cpufreq-set -c 0 -r -f 1.60GHz
cpufreq-set -c 1 -r -f 1.60GHz

...where the 1.60GHZ number came from running cpufreq-info and noting
the maximum frequency. I've got 2 cores on the laptop, so there are
2 commands. If I had 4 cores, I'd add these:

cpufreq-set -c 2 -r -f 1.60GHz
cpufreq-set -c 3 -r -f 1.60GHz

On my old laptop, this works fine and doesn't cause any problems. However
I wouldn't trust this blindly, I'd watch the output of 'sensors' to make
sure it's not causing overheating.

The above relies on the userspace governor being available, it's built in
(not a module) in both the huge and generic kernels.