Re: Severe performance regression w/ 4.4+ on Android due to cgroup locking changes

[John Stultz]

On Wed, Jul 13, 2016 at 2:42 PM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> On Wed, Jul 13, 2016 at 02:18:41PM -0700, Paul E. McKenney wrote:
>> On Wed, Jul 13, 2016 at 05:05:26PM -0400, Tejun Heo wrote:
>> > On Wed, Jul 13, 2016 at 02:03:15PM -0700, Paul E. McKenney wrote:
>> > > Take the patch that I just sent out and make the choice of normal
>> > > vs. expedited depend on CONFIG_PREEMPT_RT or whatever the -rt guys are
>> > > calling it these days.  Is there a low-latency Kconfig option other
>> > > than CONFIG_NO_HZ_FULL?
>> >
>> > Sounds like a plan to me.
>>
>> I like the way we like each other's idea.  Mutually assured laziness?  ;-)
>
> But here is what mine might look like.  Untested, probably does
> not even build.  Note that the default is -no- expediting, use the
> rcusync.expedited kernel parameter to enable it.

I was working on something similar, but using a config option. Would
adding a config option for the default make sense here, since I'd
probably prefer to have one less thing to always specify on the
cmdline?

thanks
-john