linux-kernel - Re: [patch v5 11/15] sched: add power/performance balance allow flag

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Message-ID: <20130220121256.GD16775@pd.tnic>
Date:	Wed, 20 Feb 2013 13:12:56 +0100
From:	Borislav Petkov <bp@...en8.de>
To:	Alex Shi <alex.shi@...el.com>
Cc:	torvalds@...ux-foundation.org, mingo@...hat.com,
	peterz@...radead.org, tglx@...utronix.de,
	akpm@...ux-foundation.org, arjan@...ux.intel.com, pjt@...gle.com,
	namhyung@...nel.org, efault@....de, vincent.guittot@...aro.org,
	gregkh@...uxfoundation.org, preeti@...ux.vnet.ibm.com,
	viresh.kumar@...aro.org, linux-kernel@...r.kernel.org,
	morten.rasmussen@....com
Subject: Re: [patch v5 11/15] sched: add power/performance balance allow flag

On Mon, Feb 18, 2013 at 01:07:38PM +0800, Alex Shi wrote:
> If a sched domain is idle enough for regular power balance, power_lb
> will be set, perf_lb will be clean. If a sched domain is busy,
> their value will be set oppositely.
> 
> If the domain is suitable for power balance, but balance should not
> be down by this cpu(this cpu is already idle or full), both of perf_lb
>  and power_lb are cleared to wait a suitable cpu to do power balance.
> That mean no any balance, neither power balance nor performance balance
> will be done on this cpu.
> 
> Above logical will be implemented by incoming patches.
> 
> Signed-off-by: Alex Shi <alex.shi@...el.com>
> ---
>  kernel/sched/fair.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> index 2e8131d..0047856 100644
> --- a/kernel/sched/fair.c
> +++ b/kernel/sched/fair.c
> @@ -4053,6 +4053,8 @@ struct lb_env {
>  	unsigned int		loop;
>  	unsigned int		loop_break;
>  	unsigned int		loop_max;
> +	int			power_lb;  /* if power balance needed */
> +	int			perf_lb;   /* if performance balance needed */

Those look like they're used like simple boolean flags. Why not make
them such, i.e. bitfields? See struct perf_event_attr for an example.

Thanks.

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
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