On 12/11/2013 11:31 PM, Frederic Weisbecker wrote:
OK, I'll bite... Why not just use CONFIG_NO_HZ_FULL_SYSIDLE=y with CONFIG_NO_HZ_FULL_SYSIDLE_SMALL set to at least the number of CPUs on your system? The default for CONFIG_NO_HZ_FULL_SYSIDLE_SMALL is eight. This stuff is in mainline, though Frederic's exploitation of it is still in the works.
On smaller systems, with Frederic's latest work, this should allow CPU 0 to go idle quickly.
What are you needing that this would not provide?
Yeah I think that's what he needs, but we haven't much advertized that feature yet. I mean there are good reasons, it's not yet working :o)
Many thanks for Paul and Frederic's comments!
yes, I enabled FULL_SYSIDLE with FULL_SYSIDLE_SMALL=2, but as Frederic said they are not yet working.
But yeah Alex, I'm working on plugging the full system idle detection (CONFIG_NO_HZ_FULL_SYSIDLE=y) to shutdown the timekeeping CPUs adaptively.
I have the patches ready, I'm just polishing a few things, writing changelogs, then I'll send to LKML with you Cc'ed :)
I am very glad to hear this. looking forward to seeing your patch soon. :)