Re: [PATCH 0/2] pseries/hotplug: Change the default behaviour of cede_offline

Nathan Lynch
2019-09-18T17:08:59Z

Gautham R Shenoy <ego@linux.vnet.ibm.com> writes:
> The accounting problem in tools such as lparstat with
> "cede_offline=on" is affecting customers who are using these tools for
> capacity-planning. That problem needs a fix in the short-term, for
> which Patch 1 changes the default behaviour of cede_offline from "on"
> to "off". Since this patch would break the existing userspace tools
> that use the CPU-Offline infrastructure to fold CPUs for saving power,
> the sysfs interface allowing a runtime change of cede_offline_enabled
> was provided to enable these userspace tools to cope with minimal
> change.

So we would be putting users in the position of choosing between folding
and correct accounting. :-(

Actually how does changing the offline mechanism to stop-self break the
folding utility?