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From: Dave Hansen <dave.hansen@intel.com>
To: "Limonciello, Mario" <Mario.Limonciello@amd.com>,
	"Nayak, K Prateek" <KPrateek.Nayak@amd.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "rafael@kernel.org" <rafael@kernel.org>,
	"lenb@kernel.org" <lenb@kernel.org>,
	"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
	"linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
	"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
	"bp@alien8.de" <bp@alien8.de>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"andi@lisas.de" <andi@lisas.de>,
	"puwen@hygon.cn" <puwen@hygon.cn>,
	"peterz@infradead.org" <peterz@infradead.org>,
	"rui.zhang@intel.com" <rui.zhang@intel.com>,
	"gpiccoli@igalia.com" <gpiccoli@igalia.com>,
	"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
	"Narayan, Ananth" <Ananth.Narayan@amd.com>,
	"Shenoy, Gautham Ranjal" <gautham.shenoy@amd.com>,
	"Ong, Calvin" <Calvin.Ong@amd.com>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>
Subject: Re: [PATCH] ACPI: processor_idle: Skip dummy wait for processors based on the Zen microarchitecture
Date: Thu, 22 Sep 2022 11:17:53 -0700	[thread overview]
Message-ID: <9d3d3424-a6d4-4076-87ff-a1c216de79c6@intel.com> (raw)
In-Reply-To: <MN0PR12MB610110D90985366A4B952CCCE24E9@MN0PR12MB6101.namprd12.prod.outlook.com>

On 9/22/22 10:48, Limonciello, Mario wrote:
> 
> 2) The title says to limit it to old intel systems, but nothing about this actually enforces that.
> It actually is limited to all Intel systems, but effectively won't be used on anything but new
> ones because of intel_idle.
> 
> As an idea for #2 you could check for CONFIG_INTEL_IDLE in the Intel case and
> if it's not defined show a pr_notice_once() type of message trying to tell people to use
> Intel Idle instead for better performance.

What does that have to do with *this* patch, though?

If you've got CONFIG_INTEL_IDLE disabled, you'll be slow before this
patch.  You'll also be slow after this patch.  It's entirely orthogonal.

I can add a "Practically" to the subject so folks don't confuse it with
some hard limit that is being enforced:

	ACPI: processor idle: Practically limit "Dummy wait" workaround to old
Intel systems

BTW, is there seriously a strong technical reason that AMD systems are
still using this code?  Or is it pure inertia?

  reply	other threads:[~2022-09-22 18:17 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-21  6:36 [PATCH] ACPI: processor_idle: Skip dummy wait for processors based on the Zen microarchitecture K Prateek Nayak
2022-09-21  8:47 ` Borislav Petkov
2022-09-21 10:39   ` K Prateek Nayak
2022-09-21 13:10     ` Borislav Petkov
2022-09-21 14:15 ` Dave Hansen
2022-09-21 19:51   ` Borislav Petkov
2022-09-21 19:55     ` Limonciello, Mario
2022-09-22  3:58     ` Ananth Narayan
2022-09-22  5:44   ` K Prateek Nayak
     [not found]   ` <20220923160106.9297-1-ermorton@ericmoronsm1mbp.amd.com>
2022-09-23 16:15     ` Ananth Narayan
2022-09-21 15:00 ` Peter Zijlstra
2022-09-21 19:48   ` Borislav Petkov
2022-09-22  8:17     ` Peter Zijlstra
2022-09-22 15:21       ` Rafael J. Wysocki
2022-09-22 15:36         ` Borislav Petkov
2022-09-22 15:53           ` Rafael J. Wysocki
2022-09-22 16:36             ` Dave Hansen
2022-09-22 16:44 ` Dave Hansen
2022-09-22 16:54   ` K Prateek Nayak
2022-09-22 17:01     ` Dave Hansen
2022-09-22 17:48       ` Limonciello, Mario
2022-09-22 18:17         ` Dave Hansen [this message]
2022-09-22 18:28           ` Limonciello, Mario
2022-09-23 11:47             ` Ananth Narayan
2022-09-22 19:42       ` Andreas Mohr
2022-09-22 20:10         ` Andreas Mohr
2022-09-22 21:21           ` Dave Hansen
2022-09-22 21:38             ` Limonciello, Mario
2022-09-23  7:42             ` Peter Zijlstra
2022-09-23  7:57             ` Peter Zijlstra

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