How to get CPU frequency and how to overclock it?

I have StarFive VisionFive and I tried to get cpu frequency but I failed
what is best why to get CPU freq in GHz and how I can overclock it because I have fan and I build rust project and cpu didn’t get hot or warm so I can overclock to about 2GHz or more

Please input cat /sys/devices/system/cpu/cpu0/cpu_capacity to get it .
The operating frequency is locked at 1.0GHz and cannot be overclocked.

It output 1024 for both cpu0 and cpu1،
About overclock is it hardware limit or operating system?

It is hardware limit, both 1.0GHz

Hmm, why there not way to overclock?

this is important feature :slight_smile:
it most be in next version (+ M.2 or PCIe and Open Source GPU) :+1:

I don’t think overclocking is much of a need at this point in the timeline for RISC-V. It’s not that there are any killerapps that need that extra bit of performance running on RISC-V only. Neither is it that the RISC-V ecosystem has a stability base-line that would justify having variable instability introducing bus/cpu-clock multipliers yet.

If you need HPC performance, RISC-V may not yet be for you. I recommend having a look at RaptorCS’s Talos II or Blackbird with POWER9 chips in that regard if you value your freedom over using cheap Wintel.

Overclocking important even for small soc because it allow you to get more power if you need

same thing for raspberry pi and laptops and now modern PCs
it not matter which arch you use and 100MHz make different

I understand that one may need performance and would be willing to risk it with overclocking. With RISC-V there is stability first at the moment I guess.

It is somewhat tragic though that many review articles put the Visionfive V1 in the 1.5Ghz category.

I don’t care if it dangerous or not but I’m sure it important feature that most implement in next version

Taking into account that with the tiny provided fan installed on the VisionFive, the temperature never went higher than 31 degreesC during 5 hours of compiling the Scipy package from source yesterday, I have to say the 1.0 Ghz seems extremely conservative decision.
After all the SiFive Unmatched with the U740 SoC has 4 of the same cores clocked at 1.5 Ghz!
That 50% faster performance at 1.5Ghz could have helped a lot in those 5 hours of compiling!

1 Like

and I can cool it with nitrogen, water radiator or tower fan if I want more preference

1 Like

It’s very annoying that companies advertise something as 1.5 GHz and then when you actually get it they say “Oh, no, we only support 1.0 GHz”. It’s a significant difference.

I don’t think SiFive ever actually said the Unmatched does 1.5 GHz. The buildroot SD card that came with it was set to 1.2 GHz. The Ubuntu images that quickly appeared were set to 1.0 GHz, but it’s easy to replace uboot to change this and I’ve been running mine at 1.4 GHz for the last year. I tried 1.5 GHz and it seemed fine under light load, but when I started doing some big software package builds I’d get gcc crashes after an hour or two. The temperature was never excessive, I think it just comes down to some timing issue in a worst-case pipeline (or similar) state. But 1.4 has give absolutely no problems at all. I think SiFive has since agreed 1.4 is fine on all boards they’ve tested.

The HiFive Unleashed had some Linux driver mechanism to change clock speed on the fly by writing to a /proc file. I don’t think that ability has ever been made available for the Unmatched … it’s got to be done in uboot.