i.mx6q cpu frequency question!

kangmw086 — Fri, 10 May 2019 05:52:10 GMT

I am using I.MX6Q.

From the cpufreq-info command

root@imx6qsabreauto:~# cpufreq-info

cpufrequtils 008: cpufreq-info (C) Dominik Brodowski 2004-2009
Report errors and bugs to cpufreq@vger.kernel.org, please.
analyzing CPU 0:
driver: imx6q-cpufreq
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: 109 us.
hardware limits: 396 MHz - 996 MHz
available frequency steps: 396 MHz, 792 MHz, 996 MHz
available cpufreq governors: interactive, conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 396 MHz and 996 MHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 396 MHz (asserted by call to hardware).
cpufreq stats: 396 MHz:92.91%, 792 MHz:2.17%, 996 MHz:4.91% (26)
analyzing CPU 1:
driver: imx6q-cpufreq
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: 109 us.
hardware limits: 396 MHz - 996 MHz
available frequency steps: 396 MHz, 792 MHz, 996 MHz
available cpufreq governors: interactive, conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 396 MHz and 996 MHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 396 MHz (asserted by call to hardware).
cpufreq stats: 396 MHz:92.91%, 792 MHz:2.17%, 996 MHz:4.91% (26)
analyzing CPU 2:
driver: imx6q-cpufreq
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: 109 us.
hardware limits: 396 MHz - 996 MHz
available frequency steps: 396 MHz, 792 MHz, 996 MHz
available cpufreq governors: interactive, conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 396 MHz and 996 MHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 396 MHz (asserted by call to hardware).
cpufreq stats: 396 MHz:92.91%, 792 MHz:2.17%, 996 MHz:4.91% (26)
analyzing CPU 3:
driver: imx6q-cpufreq
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: 109 us.
hardware limits: 396 MHz - 996 MHz
available frequency steps: 396 MHz, 792 MHz, 996 MHz
available cpufreq governors: interactive, conservative, userspace, powersave, ondemand, performance
current policy: frequency should be within 396 MHz and 996 MHz.
The governor "ondemand" may decide which speed to use
within this range.
current CPU frequency is 396 MHz (asserted by call to hardware).
cpufreq stats: 396 MHz:92.91%, 792 MHz:2.17%, 996 MHz:4.91% (26)

I currently seem to be using the CPU clock frequency 396MHz.

1. Does the frequency vary by 396,792,996 MHz depending on CPU usage? (automatic?)

2. To change the CPU operating frequency, do you need to change it to echo 996000> / sys / devices / system / cpu / cpu0 / cpufreq / scaling_setspeed after booting is complete?

3. Can I change it in the kernel source?

4. How high is the power consumption when the frequency is high?

regards!!

Re: i.mx6q cpu frequency question!

igorpadykov — Fri, 10 May 2019 10:23:35 GMT

Hi k

1. right, frequency changes automatically

2. one can refer to Chapter 23 CPU Frequency Scaling (CPUFREQ) Driver

attached Linux Manual.

3.4. for power consumption one can look at AN4509

i.MX 6Dual/6Quad Power Consumption Measurement

sect.6.1. Current vs. frequency AN5381

Measuring Current in i.MX Applications

Best regards
igor
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i.mx6q cpu frequency question!

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