Re: BUG: sched_mc_powersavings broken on pre-Nehalem x86 platforms

From: Peter Zijlstra
Date: Mon Feb 08 2010 - 06:36:10 EST


On Mon, 2010-02-08 at 15:35 +0530, Vaidyanathan Srinivasan wrote:

> Fix for sched_mc_powersavigs for pre-Nehalem platforms.
> Child sched domain should clear SD_PREFER_SIBLING if parent will have
> SD_POWERSAVINGS_BALANCE because they are contradicting.
>
> Sets the flags correctly based on sched_mc_power_savings.
>
> Signed-off-by: Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx>
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 6550415..ef6b7cd 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -866,7 +866,10 @@ static inline int sd_balance_for_mc_power(void)
> if (sched_smt_power_savings)
> return SD_POWERSAVINGS_BALANCE;
>
> - return SD_PREFER_SIBLING;
> + if (!sched_mc_power_savings)
> + return SD_PREFER_SIBLING;
> +
> + return 0;
> }
>
> static inline int sd_balance_for_package_power(void)
>

Looks good, thanks!

What's the status of getting rid of sched_{mc,smt}_power_savings?

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