On Tue, May 12, 2015 at 11:26:07AM +0200, Peter Zijlstra wrote:
On Fri, May 08, 2015 at 01:58:43PM -0400, Chris Metcalf wrote:It will at least provide an environment where adding more of this
While the current fallback to 1-second tick is still helpful forSo how is making this available going to help people fix the actual
maintaining completely correct kernel semantics, processes using
prctl(PR_SET_DATAPLANE) semantics place a higher priority on running
completely tickless, so don't bound the time_delta for such processes.
This was previously discussed in
and Thomas Gleixner observed that vruntime, load balancing data,
load accounting, and other things might be impacted. Frederic
Weisbecker similarly observed that allowing the tick to be indefinitely
deferred just meant that no one would ever fix the underlying bugs.
However it's at least true that the mode proposed in this patch can
only be enabled on an isolcpus core, which may limit how important
it is to maintain scheduler data correctly, for example.
problem might get punished. This would be an improvement over what
we have today, namely that the 1HZ fallback timer silently forgives
adding more problems of this sort.