On Fri, Aug 11, 2017 at 08:36:28AM +0200, Mike Galbraith wrote: > 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.
Indeed we probably shouldn't introduce new config that affine housekeeping to a single CPU. > Personally, I think NOHZ_FULL_ALL should just die. Yeah, although it's still useful for automatic boot testing to detect issues with nohz_full on. Thanks.
