Messages in this thread | | | Date | Thu, 31 Jan 2013 11:30:59 +0100 | Subject | Re: [PATCH 8/8] cputime: Safely read cputime of full dynticks CPUs | From | Sedat Dilek <> |
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On Thu, Jan 31, 2013 at 11:12 AM, Frederic Weisbecker <fweisbec@gmail.com> wrote: > 2013/1/31 Sedat Dilek <sedat.dilek@gmail.com>: >> On Thu, Jan 31, 2013 at 1:38 AM, Frederic Weisbecker <fweisbec@gmail.com> wrote: >>> 2013/1/28 Sedat Dilek <sedat.dilek@gmail.com>: >>>> On Mon, Jan 28, 2013 at 8:04 PM, Frederic Weisbecker <fweisbec@gmail.com> wrote: >>>>> While remotely reading the cputime of a task running in a >>>>> full dynticks CPU, the values stored in utime/stime fields >>>>> of struct task_struct may be stale. Its values may be those >>>>> of the last kernel <-> user transition time snapshot and >>>>> we need to add the tickless time spent since this snapshot. >>>>> >>>>> To fix this, flush the cputime of the dynticks CPUs on >>>>> kernel <-> user transition and record the time / context >>>>> where we did this. Then on top of this snapshot and the current >>>>> time, perform the fixup on the reader side from task_times() >>>>> accessors. >>>>> >>>>> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> >>>>> Cc: Andrew Morton <akpm@linux-foundation.org> >>>>> Cc: Ingo Molnar <mingo@kernel.org> >>>>> Cc: Li Zhong <zhong@linux.vnet.ibm.com> >>>>> Cc: Namhyung Kim <namhyung.kim@lge.com> >>>>> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> >>>>> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> >>>>> Cc: Peter Zijlstra <peterz@infradead.org> >>>>> Cc: Steven Rostedt <rostedt@goodmis.org> >>>>> Cc: Thomas Gleixner <tglx@linutronix.de> >>>>> [fixed kvm module related build errors] >>>>> Signed-off-by: Sedat Dilek <sedat.dilek@gmail.com> >>>>> >>>> >>>> Can you explain a bit what is the difference between "3.8-rc4-nohz3" >>>> and "full-dynticks-cputime-for-mingo" patchsets? >>> >>> 3.8-rc4-nohz3 is the latest experimental tree that implements full >>> dynticks. It includes an earlier version of full dynticks cputime and >>> many other things to make the full dynticks possible: nohz printk, >>> many tweaks on the scheduler and timers...etc >>> >> >> So, dynticks-cputime will go into 3.9? > > I can't say "will" but I hope. > >> What about the other parts? Coming later? > > May be the printk part will go into 3.9. Linus ignored my pull request > so may be we'll get more chances if it goes through Ingo. >
I still dunno all parts of dynticks and their correlation. AFAICS they seem to be independent, can't say if it is "complete" with dynticks-cputime-only.
Was that dynticks stuff ever advertised for Linux-Next inclusion? Or wnt through any "mingo-next" tree? AFAICS, better chances these ways!
- Sedat -
> And the rest will come later.
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