Re: [PATCH 3/4] sched: Optimize tick periodic cpu load updates

From	Peter Zijlstra <peterz@infradead.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/4] sched: Optimize tick periodic cpu load updates
Date	2016-04-02 09:30 +0200
Message-ID	<rjoal-pV-7@gated-at.bofh.it> (permalink)
References	<rj7jb-4UU-9@gated-at.bofh.it> <rj7jb-4UU-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, Apr 01, 2016 at 03:23:06PM +0200, Frederic Weisbecker wrote:
> Don't bother with the whole pending tickless cpu load machinery if
> we run a tick periodic kernel. That's less job for the CPU on ticks.

Again, the changelog really could use help. Is this a pure optimization
patch? If so, do you have numbers?

> +++ b/kernel/sched/sched.h
> @@ -585,8 +585,10 @@ struct rq {
>  #endif
>  	#define CPU_LOAD_IDX_MAX 5
>  	unsigned long cpu_load[CPU_LOAD_IDX_MAX];
> +#ifdef CONFIG_NO_HZ_COMMON
> +# ifdef CONFIG_SMP

I'm not a fan of this #ifdef indenting and nothing near there uses this
style, so please don't introduce it here.

>  	unsigned long last_load_update_tick;
> -#ifdef CONFIG_NO_HZ_COMMON
> +# endif
>  	u64 nohz_stamp;
>  	unsigned long nohz_flags;
>  #endif
> -- 
> 2.7.0
>

Thread

[PATCH 3/4] sched: Optimize tick periodic cpu load updates Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-01 15:30 +0200
  Re: [PATCH 3/4] sched: Optimize tick periodic cpu load updates Peter Zijlstra <peterz@infradead.org> - 2016-04-02 09:30 +0200
    Re: [PATCH 3/4] sched: Optimize tick periodic cpu load updates Frederic Weisbecker <fweisbec@gmail.com> - 2016-04-02 14:40 +0200

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