Re: [PATCH v5 1/2] timers: Don't wake ktimersoftd on every tick

[Haris Okanovic]

Sounds good. I'll keep an eye out for your patch set and try it on my 
boards as well. CC me if you can.

-- Haris


On 07/13/2018 07:01 AM, Anna-Maria Gleixner wrote:
> Hi Haris,
>
> On Thu, 28 Jun 2018, Haris Okanovic wrote:
>
> > Collect expired timers in interrupt context to avoid overhead of waking
> > ktimersoftd on every scheduler tick.
> >
> > This is implemented by storing lists of expired timers in the timer_base
> > struct, which is updated by the interrupt routing on each tick in
> > run_local_timers(). TIMER softirq (ktimersoftd) is then raised only when
> > one or more expired timers are collected.
> >
> > Performance impact on a 2core Intel Atom E3825 system:
> >   * reduction in small latency spikes measured by cyclictest
> >   * ~30% fewer context-switches measured by perf
> >   * run_local_timers() execution time increases by 0.2 measured by TSC
>
> I'm also working on timer improvements at the moment. When I fixed all
> my bugs in my implementation (there is a last horrible one), I'm very
> interested in integrating your patches into my testing to be able to
> give you a tested-by.
>
> Thanks,
>
> 	Anna-Maria