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