Re: [PATCH 3/3] sched: Optimize !CONFIG_NO_HZ_COMMON cpu load updates

[Peter Zijlstra]

On Fri, Apr 08, 2016 at 02:55:22PM +0200, Frederic Weisbecker wrote:
> > > @@ -4540,17 +4568,8 @@ static void cpu_load_update(struct rq *this_rq, unsigned long this_load,
> > >  
> > >  		/* scale is effectively 1 << i now, and >> i divides by scale */
> > >  
> > > -		old_load = this_rq->cpu_load[i];
> > #ifdef CONFIG_NO_HZ_COMMON
> > > -		old_load = decay_load_missed(old_load, pending_updates - 1, i);
> > > -		if (tickless_load) {
> > > -			old_load -= decay_load_missed(tickless_load, pending_updates - 1, i);
> > > -			/*
> > > -			 * old_load can never be a negative value because a
> > > -			 * decayed tickless_load cannot be greater than the
> > > -			 * original tickless_load.
> > > -			 */
> > > -			old_load += tickless_load;
> > > -		}
> > #endif
> 
> Ah sure, if you prefer it that way, I can do that.

Yes please. I normally favour the thing you did, but here it makes
tricky code that much harder to read.