linux-kernel - Re: [PATCH] x86, acpi, idle: Restructure the mwait idle routines

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Message-ID: <528B7433.7020507@linux.intel.com>
Date:	Tue, 19 Nov 2013 06:22:43 -0800
From:	Arjan van de Ven <arjan@...ux.intel.com>
To:	Peter Zijlstra <peterz@...radead.org>, lenb@...nel.org,
	rjw@...ysocki.net, linux-acpi@...r.kernel.org,
	linux-kernel@...r.kernel.org
CC:	shaohua.li@...el.com, rui.zhang@...el.com,
	jacob.jun.pan@...ux.intel.com,
	Mike Galbraith <bitbucket@...ine.de>,
	Ingo Molnar <mingo@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>, hpa@...or.com
Subject: Re: [PATCH] x86, acpi, idle: Restructure the mwait idle routines

> diff --git a/drivers/thermal/intel_powerclamp.c b/drivers/thermal/intel_powerclamp.c
> index 8f181b3f842b..e8275f2df9af 100644
> --- a/drivers/thermal/intel_powerclamp.c
> +++ b/drivers/thermal/intel_powerclamp.c
> @@ -438,9 +438,7 @@ static int clamp_thread(void *arg)
>   			 */
>   			local_touch_nmi();
>   			stop_critical_timings();
> -			__monitor((void *)&current_thread_info()->flags, 0, 0);
> -			cpu_relax(); /* allow HT sibling to run */
> -			__mwait(eax, ecx);
> +			mwait_idle_with_hints(eax, ecx);
>   			start_critical_timings();
>   			atomic_inc(&idle_wakeup_counter);
>   		}
>

hmm I take it that mwait_idle_with_hints is the one that also checks need_resched() ?
if so... powerclamp may not want to use that (the whole point is to NOT give the cpu
to tasks!)
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