Re: Periodic rant about SCHED_ULE

From: David Chisnall <>
Date: Thu, 23 Mar 2023 10:03:36 UTC
On 22/03/2023 18:03, George Mitchell wrote:
> Rebuilding the kernel is the only way I know.  In an ideal world, the
> scheduler would be a loadable kernel module (if that's even possible),

Solaris supports multiple schedulers, as I believe does Linux, but I 
think in both cases it's a boot-time option.  It's been too long since I 
looked at the early boot order to know if there's anything that handles 
linking the loader-provided modules that depends on any scheduler data 
structures.  Doing that audit and ensuring that there aren't would be 
the first step.  From there, it should be mostly build-system 
infrastructure to allow building the two schedulers as modules and 
switching between them at boot.

Allowing switching schedulers after boot time is a much harder problem. 
I know some microkernels have done it, but even there (where the 
scheduler is a separate service) it's far from easy.