| Date | Mon, 21 Jan 2019 16:17:17 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v6 04/16] sched/core: uclamp: Add CPU's clamp buckets refcounting |
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On Tue, Jan 15, 2019 at 10:15:01AM +0000, Patrick Bellasi wrote: > +#ifdef CONFIG_UCLAMP_TASK
> +struct uclamp_bucket { > + unsigned long value : bits_per(SCHED_CAPACITY_SCALE); > + unsigned long tasks : BITS_PER_LONG - bits_per(SCHED_CAPACITY_SCALE); > +};
> +struct uclamp_cpu { > + unsigned int value;
/* 4 byte hole */
> + struct uclamp_bucket bucket[UCLAMP_BUCKETS]; > +};
With the default of 5, this UCLAMP_BUCKETS := 6, so struct uclamp_cpu ends up being 7 'unsigned long's, or 56 bytes on 64bit (with a 4 byte hole).
> +#endif /* CONFIG_UCLAMP_TASK */ > + > /* > * This is the main, per-CPU runqueue data structure. > * > @@ -835,6 +879,11 @@ struct rq { > unsigned long nr_load_updates; > u64 nr_switches; > > +#ifdef CONFIG_UCLAMP_TASK > + /* Utilization clamp values based on CPU's RUNNABLE tasks */ > + struct uclamp_cpu uclamp[UCLAMP_CNT] ____cacheline_aligned;
Which makes this 112 bytes with 8 bytes in 2 holes, which is short of 2 64 byte cachelines.
Is that the best layout?
> +#endif > + > struct cfs_rq cfs; > struct rt_rq rt; > struct dl_rq dl; > -- > 2.19.2 >
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