On Thu, 2017-08-10 at 09:57 -0400, Chris Metcalf wrote: > On 8/10/2017 8:54 AM, Frederic Weisbecker wrote: > > But perhaps I should add a new NO_HZ_FULL_BUT_HOUSEKEEPING option. > > Otherwise we'll change the meaning of NO_HZ_FULL_ALL way too much, to the > > point > > that its default behaviour will be the exact opposite of the current one: > > by default > > every CPU is housekeeping, so NO_HZ_FULL_ALL would have no effect anymore > > if we > > don't set housekeeping boot option. > > Maybe a CONFIG_HOUSEKEEPING_BOOT_ONLY as a way to restrict housekeeping > by default to just the boot cpu. In conjunction with NOHZ_FULL_ALL you would > then get the expected semantics.
A big box with only the boot cpu for housekeeping is likely screwed. Personally, I think NOHZ_FULL_ALL should just die. -Mike