Re: [PATCH] smp: Add bootcpus parameter to boot subset of CPUs

From: Peter Zijlstra
Date: Fri Oct 23 2020 - 03:45:50 EST


On Thu, Oct 22, 2020 at 03:04:03PM -0700, Elliot Berman wrote:
> In a heterogeneous multiprocessor system, specifying the 'maxcpus'
> parameter on kernel command line does not provide sufficient control
> over which CPUs are brought online at kernel boot time, since CPUs may
> have nonuniform performance characteristics. Thus, add bootcpus kernel
> parameter to control which CPUs should be brought online during kernel
> boot. When both maxcpus and bootcpus is set, the more restrictive of the
> two are booted.

Why would one wish to do so? Having the ability for abilities sake is no
good.