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Cpu frequency Nano NEO2

Posted: Mon Aug 28, 2017 4:39 pm
by ulorentz
Hi!
I've recently bought the Nano NEO 2, it has a H5 soc and on friendly arm says it runs a 1.5ghz. Looking into /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq it says 1008000, so more or less 1GHz (a lot less than 1.5...). The same in sclaling_max_freq and in scaling_available_frequencies. Not fair! How to clock to the claimed 1.5Ghz?
Thanks

Re: Cpu frequency Nano NEO2

Posted: Wed Aug 30, 2017 1:34 pm
by meisam
ulorentz wrote:
Hi!
I've recently bought the Nano NEO 2, it has a H5 soc and on friendly arm says it runs a 1.5ghz. Looking into /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq it says 1008000, so more or less 1GHz (a lot less than 1.5...). The same in sclaling_max_freq and in scaling_available_frequencies. Not fair! How to clock to the claimed 1.5Ghz?
Thanks




there is a '"governor" file in the /sys/devices/system/cpu... , you can change the value by "echo" command to change the cpu frequency, but cpu frequency auto scale may over write your settings soon.

better way is to change the "min frequency" to your appropriate value in every startup !

Re: Cpu frequency Nano NEO2

Posted: Thu Aug 31, 2017 10:03 am
by ulorentz
No, the problem it is not a software problem. Is or a kernel problem or an hardware one. If you run cpufreq-info you get:
analyzing CPU 3:
driver: cpufreq-dt
CPUs which run at the same hardware frequency: 0 1 2 3
CPUs which need to have their frequency coordinated by software: 0 1 2 3
maximum transition latency: 244 us.
hardware limits: 120 MHz - 1.01 GHz
available frequency steps: 120 MHz, 240 MHz, 312 MHz, 480 MHz, 624 MHz, 816 MHz, 1.01 GHz
available cpufreq governors: conservative, ondemand, userspace, powersave, performance, schedutil
current policy: frequency should be within 120 MHz and 1.01 GHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 1.01 GHz (asserted by call to hardware).
cpufreq stats: 120 MHz:58.40%, 240 MHz:0.75%, 312 MHz:0.82%, 480 MHz:0.47%, 624 MHz:0.65%, 816 MHz:0.64%, 1.01 GHz:38.28% (66)

This means that the kernel limit is 1.01GHz, no matter what you write in those file: you won't be able to get an higher frequency than 1.01. I wonder how is possible that no one realized before that the Nano NEO2 can't reach 1.5Ghz. I don't know if it's just a problem of the image, a problem of the H5 or a problem of the board, but whatever is the reason FriendlyArm shoudn't claim 1.5Ghz on its website, having only 60% of the frequency is a problem for me, I choosed that board for it's performance, if I had known that I would had bought another board.

Re: Cpu frequency Nano NEO2

Posted: Thu Aug 31, 2017 9:01 pm
by meisam
Ok. Just i got your mean, this is a kernel problem should be answered by the friendlyarm developers!
But i guess that thermal issues cause this limitation in practice.