Re: [RFC V2 2/2] sched: idle: IRQ based next prediction for idle period
From: Peter Zijlstra
Date: Wed Jan 20 2016 - 14:40:18 EST
On Wed, Jan 20, 2016 at 05:00:33PM +0100, Daniel Lezcano wrote:
> +static inline u32 stats_mean(struct stats *s)
> + /*
> + * gcc is smart enough to convert to a bits shift when the
> + * divisor is constant and multiple of 2^x.
> + *
> + * The number of values could have not reached STATS_NR_VALUES
> + * yet, but we can consider it acceptable as the situation is
> + * only at the beginning of the burst of irqs.
> + */
> + return s->sum / STATS_NR_VALUES;
Note that ->sum is u64, so you're very prone to truncation.