Yes; check my blog post [1] or latest YouTube video [2] for details, but the tldr is 0.4W (80 mA) idle minimum for Zero W, 0.6W (100 mA) idle minimum for Zero W 2.
Zero W goes up to 160 mA at load, while Zero W 2 gets up to 400-500 mA due to the three extra CPU cores.
Another comment says /sys/devices/system/cpu/cpu[0-n]/online doesn't work, but I think you can get pretty far by changing the CPU affinity at the cgroup or process levels (for userspace) and on /proc/irq/default_smp_affinity (for interrupts). There are likely some kernel threads that would still run on the other cores, but this is reasonably close.
In particular, looks like setting CPUAffinity= /etc/systemd/system.conf will set a default for all of userspace that you can override for particular things as desired.
Comments
Do you have power consumption numbers? Compared to the Pi Zero W, hom much more does it consumes?
Yes; check my blog post [1] or latest YouTube video [2] for details, but the tldr is 0.4W (80 mA) idle minimum for Zero W, 0.6W (100 mA) idle minimum for Zero W 2.
Zero W goes up to 160 mA at load, while Zero W 2 gets up to 400-500 mA due to the three extra CPU cores.
[1] https://www.jeffgeerling.com/blog/2021/look-inside-raspberry...
[2] https://www.youtube.com/watch?v=lKS2ElWQizA
That's a big jump. Is there a way of getting Linux to disable a couple of cores?
`echo 0 > /sys/devices/system/cpu/cpu[0-n]/online` should do what you want.
Even as root, that gives `permission denied` on Pi OS on the Zero 2 W. I'm trying the kernel cmdline option too.
Edit: That works! See: https://www.jeffgeerling.com/blog/2021/disabling-cores-reduc...
Well… I said it should, not that it would. ;-)
On x86 there was an option, i think nr_cpus or something like that some time ago. There was also SMP_KERNEL kernel config option.
2W! Did you measure Gflops? I wish you could disable cores dynamically...
That's why they called it Pi Zero 2 W and not Pi Zero W 2, which is what it is.
Another comment says /sys/devices/system/cpu/cpu[0-n]/online doesn't work, but I think you can get pretty far by changing the CPU affinity at the cgroup or process levels (for userspace) and on /proc/irq/default_smp_affinity (for interrupts). There are likely some kernel threads that would still run on the other cores, but this is reasonably close.
In particular, looks like setting CPUAffinity= /etc/systemd/system.conf will set a default for all of userspace that you can override for particular things as desired.
you can: https://news.ycombinator.com/item?id=29024994
Is undervolting an option?