Messages in this thread | | | Date | Sat, 9 Mar 2013 09:26:50 +0100 | From | Ingo Molnar <> | Subject | Re: [ANNOUNCE] 3.9-rc1-nohz1 |
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* Frederic Weisbecker <fweisbec@gmail.com> wrote:
> Hi, > > Several fixes there. And this version should have much lesser spurious warnings. > Your testing and reviews is very appreciated. > > The 5 first patches of the series are pending on a pull request for -tip (3.10 > material). > > I'm now considering how I should upstream the rest of the series. All the pieces > that got merged until now were sort of easy because the various chunks were pretty > self contained and independant (full dynticks cputime accounting, printk, RCU user > mode, dynticks API generalization, etc...). > > Now what remains in this series is hard to cut into individual parts. Everything > depends on defining an interface with kernel parameter to partition the full > dynticks CPUs set. > > I think we really need to start using a branch in -tip and move incrementally from > there with the following steps: > > 1) Set the kernel parameters and config option > 2) Handle timers wakeup, timekeeping, posix cpu timers, perf, sched etc... > on top of kernel parameter based CPU partition > 3) Once we know _everything_ is handled, bring the final dynticks infrastructure > 4) Upstream > > This will make everything much easier for everyone: easier piecewise reviews and > easier for other people to contribute. > > Because you don't want me to spam you with ~40 commits for 2 more years, right? > > Thanks. > > This version can be found at: > > git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git > 3.9-rc1-nohz1 > > --- > Changes since 3.8-rc6-nohz4: > > * Rebase against 3.9-rc1 > > * Fixed a few races with exception and preemption handling [1-3/29] > > * Dropped commit "sched: Remove broken check for skip clock update" > that was buggy (thanks Steve for pointing that) > > * Ignore noisy stale rq clock detection on boot and other situations > with rq->skip_clock_update [27/29] > > * Dropped commit "sched: Update clock of nohz busiest rq before balancing" > that became useless (thanks Li Zhong) > > * Don't issue a self IPI on timer enqueue if the CPU didn't stop its > tick [9/29] > > * Rename a bit the Kconfig menu after discussion with Borislav [6/29] > > * Handle broken full_nohz mask in kernel parameters (thanks Borislav) [6/29] > > --- > TODO list hasn't changed much: > > - Posix CPU timers > - Perf events > - sched_class::task_tick() > - various other scheduler details > - ...
We could certainly start tip:sched/dynticks (or tip:timers/dynticks) to accelerate the upstream merging of it. Nobody expressed deep concerns with the approach, so what is left is some more hard work.
Two quick requests:
- Mind adding a Documentation/... file with a high level description, rough design, open problems, etc.?
- Please outline how the current TODO entries affect upstream mergability. Does it reduce the 'full'-ness of this dynticks mode? Outright buggy behavior? Other trade-offs?
Thanks,
Ingo
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