[fedora-arm] BeagleBone Black CPU speed

[Robert Nelson]

On Wed, Jan 22, 2014 at 10:32 AM, Peter Robinson <pbrobinson at gmail.com> wrote:
> Hi Robert,
>
>>> Fedora:
>>> Pystone(1.1) time for 50000 passes = 10.9073
>>> This machine benchmarks at 4584.1 pystones/second
>>
>> Which governor are you using?  It seems to be definitely stuck at 300Mhz
>
> # cpupower frequency-info
> analyzing CPU 0:
>   driver: generic_cpu0
>   CPUs which run at the same hardware frequency: 0
>   CPUs which need to have their frequency coordinated by software: 0
>   maximum transition latency: 300 us.
>   hardware limits: 300 MHz - 1000 MHz
>   available frequency steps: 300 MHz, 600 MHz, 800 MHz, 1000 MHz
>   available cpufreq governors: conservative, userspace, powersave,
> ondemand, performance
>   current policy: frequency should be within 300 MHz and 1000 MHz.
>                   The governor "ondemand" may decide which speed to use
>                   within this range.
>   current CPU frequency is 300 MHz (asserted by call to hardware).
>
>> 3.13.0-bone4 (what i'm shipping to debian bone users..)
>
> kernel-3.13.0-1.1.fc20.armv7hl
>
> [root at bblack ~]# cpupower frequency-info
> analyzing CPU 0:
>   driver: generic_cpu0
>   CPUs which run at the same hardware frequency: 0
>   CPUs which need to have their frequency coordinated by software: 0
>   maximum transition latency: 300 us.
>   hardware limits: 300 MHz - 1000 MHz
>   available frequency steps: 300 MHz, 600 MHz, 800 MHz, 1000 MHz
>   available cpufreq governors: conservative, userspace, powersave,
> ondemand, performance
>   current policy: frequency should be within 300 MHz and 1000 MHz.
>                   The governor "ondemand" may decide which speed to use
>                   within this range.
>   current CPU frequency is 300 MHz (asserted by call to hardware).
> [root at bblack ~]# /usr/lib/python2.7/test/pystone.py
> Pystone(1.1) time for 50000 passes = 6.20305
> This machine benchmarks at 8060.55 pystones/second
> [root at bblack ~]# cpupower frequency-set -f 600000
> Setting cpu: 0
> [root at bblack ~]# /usr/lib/python2.7/test/pystone.py
> Pystone(1.1) time for 50000 passes = 10.6237
> This machine benchmarks at 4706.45 pystones/second
> [root at bblack ~]# cpupower frequency-set -f 800000
> Setting cpu: 0
> [root at bblack ~]# /usr/lib/python2.7/test/pystone.py
> Pystone(1.1) time for 50000 passes = 7.76076
> This machine benchmarks at 6442.67 pystones/second
> [root at bblack ~]# cpupower frequency-set -f 1000000
> Setting cpu: 0
> [root at bblack ~]# /usr/lib/python2.7/test/pystone.py
> Pystone(1.1) time for 50000 passes = 6.16087
> This machine benchmarks at 8115.74 pystones/second
> [root at bblack ~]# cpupower frequency-info
> analyzing CPU 0:
>   driver: generic_cpu0
>   CPUs which run at the same hardware frequency: 0
>   CPUs which need to have their frequency coordinated by software: 0
>   maximum transition latency: 300 us.
>   hardware limits: 300 MHz - 1000 MHz
>   available frequency steps: 300 MHz, 600 MHz, 800 MHz, 1000 MHz
>   available cpufreq governors: conservative, userspace, powersave,
> ondemand, performance
>   current policy: frequency should be within 300 MHz and 1000 MHz.
>                   The governor "userspace" may decide which speed to use
>                   within this range.
>   current CPU frequency is 1000 MHz (asserted by call to hardware).
>
> So it appears to work but the results are some what variable. Also I
> presume you've got the cpufreq driver built in rather than a module as
> it doesn't auto load.

Yeap, it's built in..

https://github.com/RobertCNelson/linux-dev/blob/am33x-v3.13/patches/defconfig#L574

Regards,

-- 
Robert Nelson
http://www.rcn-ee.com/