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Date: Wed, 3 Aug 2016 12:34:42 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Giovanni Gherdovich <ggherdovich@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>, Mike Galbraith <mgalbraith@suse.de>,
        Stanislaw Gruszka <sgruszka@redhat.com>, linux-kernel@vger.kernel.org,
        Mel Gorman <mgorman@suse.com>, mgorman@techsingularity.net
Subject: Re: [PATCH] sched/cputime: Mitigate performance regression in
 times()/clock_gettime()
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On Wed, Aug 03, 2016 at 12:02:54PM +0200, Peter Zijlstra wrote:
> /*
>  * XXX comment on why this is needed goes here...
>  */
> static inline void prefetch_curr_exec_start(struct task_struct *p)
> {
> #ifdef CONFIG_FAIR_GROUP_SCHED
> 	struct sched_entity *curr = (&p->se)->cfs_rq->curr;
#else
	struct sched_entity *curr = task_rq(p)->cfs_rq->curr;
#endif

Would be the 'right' thing for !cgroup stuffs

> 
> 	prefetch(curr);
> 	prefetch(&curr->exec_start);
> }