Am Montag, 7. Juni 2021, 11:59:20 CEST schrieb Hannes Reinecke:
On 6/3/21 11:37 AM, Thomas Hartwig wrote:
I am wondering if there is any kernel available by default which offers kernel interrupt timer (CONFIG_HZ) at 1000 Hz. I checked preempt in 15.2 but there it is 250 Hz. Why this is kept at 250 Hz there?
Thomas, I do build some special kernels in this regard here: https://build.opensuse.org/project/monitor/home:frispete:kernel The preempt flavor is using CONFIG_HZ_1000 (of course). For now, I build this kernel for TW only (target: openSUSE_Tumbleweed_Kernel_stable). It should work with Leap as well, but I can add other targets on request. To be honest, I build the kernels for my openSUSE zoo in an internal build service (for other reasons). The kernel is based on https://github.com/openSUSE/kernel-source/commits/stable With 2 scheduler changes *rebased*: https://github.com/frispete/kernel-source/tree/stable https://github.com/frispete/kernel-source/commit/ eff66ed807d15a93ee71e192ba1ed7394dd5e917 https://github.com/frispete/kernel-source/commit/ 1affceb6384e74af3027599a17113a5fe04fd835 I would be honored, if you could give this build a try. Please note, that these kernels are signed with my build key, which might trick UEFI into complaints and forcing you to add another certificate. As you can see, I try to stick to the "official" workflow, which makes dealing with such changes a breeze.
Primarily for historical reasons; 250 Hz was found to be a good compromise between interactive and non-interactive tasks.
Sure Hannes, but with the advent of preempt, there's a new opportunity to split this compromise into: default: voluntary preempt, optimized for non-interactive tasks, maximum throughput and efficiency preempt: full preempt, optimized for low latency, less maximum performance in favor of optimal interactivity At least in my modest tests, the preempt variant with HZ=1000 provides a better user experience on busy desktops *and* crowded servers. Probably HZ=1000 is a red herring here, but even my poor Gen-1 X1 Carbon runs happily with my preempt kernels without visible adverse effects in battery endurance (which is pretty limited in this edition anyway). At least, it beats a calm Win10 desktop easily.. Of course, this doesn't replace a wider investigation, but we should try to make the most of the possibilities of two different versions. I would like to see the preempt variant to use advanced CPU and compiler optimization techniques as well, but didn't dived into this yet. What could be achieved can be seen here: https://www.phoronix.com/scan.php?page=article&item=spring-2020-distros&num=1 We should take a leaf out of the Clear Linux* Project's book. Best, Pete