On Wed Sep 30, 2026 at 3:55 PM UTC, Christian Schulte wrote: > Hi @misc, > > is there a way to manually set the "CPU clock frequency" to some > arbitrary software value, like 1MHz for testing? I am searching for a > way to test an application when run with a very limited system and would > like to just simulate such a system in software. Something like: "Make > the whole system (scheduler etc.) run as if the CPU is clocked with a > given frequency (that could be kHz, MHz - values not supported by the > hardware). Something like: > > update boot.conf to set said clock to say 500kHz > reboot > > System runs with that 500kHz on next reboot. > > Regards,
Hi Christian, As far as I know that is not possible. However, you can sysctl hw.perfpolicy=manual and then sysctl hw.setperf=0-100. You can see what clock speed you got with sysctl hw.cpuspeed. I think this is largely a hardware support thing and you'll have a range of supported speeds. Like you might have 800MHz, 1200MHz, 1800MHz, and finally 2200MHz. Sincerely, Henrich PS: If you want to test something really, really slow, use qemu without any acceleration.
