Re: [PATCH] Kconfig.hz: Change default HZ to 1000

Andrea Righi
2025-02-23T07:50:32Z

On Wed, Feb 12, 2025 at 09:50:54AM -0500, Joel Fernandes wrote:
> On Mon, Feb 10, 2025 at 12:19:15AM +0000, Qais Yousef wrote:
...
> > I believe HZ_250 was the default as a trade-off for battery power
> > devices that might not be happy with frequent TICKS potentially draining
> > the battery unnecessarily. But to my understanding the current state of
>
> Actually, on x86, me and Steve did some debug on Chromebooks and we found
> that HZ_250 actually increased power versus higher HZ. This was because
> cpuidle governor changes C states on the tick, and by making it less
> frequent, the CPU could be in a shallow C state for longer.

FWIW, I found the same about power consumption when we decided to switch to
CONFIG_HZ=1000 in the Ubuntu kernel:
https://discourse.ubuntu.com/t/enable-low-latency-features-in-the-generic-ubuntu-kernel-for-24-04/42255

-Andrea