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Date: Thu, 22 Sep 2022 17:36:20 +0200
From: Borislav Petkov <bp@alien8.de>
To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	K Prateek Nayak <kprateek.nayak@amd.com>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Len Brown <lenb@kernel.org>,
	ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
	Linux PM <linux-pm@vger.kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Thomas Gleixner <tglx@linutronix.de>, andi@lisas.de,
	Pu Wen <puwen@hygon.cn>,
	Mario Limonciello <mario.limonciello@amd.com>,
	"Zhang, Rui" <rui.zhang@intel.com>,
	"Guilherme G. Piccoli" <gpiccoli@igalia.com>,
	Daniel Lezcano <daniel.lezcano@linaro.org>, ananth.narayan@amd.com,
	gautham.shenoy@amd.com, Calvin Ong <calvin.ong@amd.com>,
	Stable <stable@vger.kernel.org>, regressions@lists.linux.dev
Subject: Re: [PATCH] ACPI: processor_idle: Skip dummy wait for processors
 based on the Zen microarchitecture
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On Thu, Sep 22, 2022 at 05:21:21PM +0200, Rafael J. Wysocki wrote:
> Well, it can be forced to use ACPI idle instead.

Yeah, I did that earlier. The dummy IO read in question costs ~3K on
average on my Coffeelake box here.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette