From: Peter Zijlstra <peterz@infradead.org>
To: Borislav Petkov <bp@alien8.de>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>,
linux-kernel@vger.kernel.org, rafael@kernel.org, lenb@kernel.org,
linux-acpi@vger.kernel.org, linux-pm@vger.kernel.org,
dave.hansen@linux.intel.com, tglx@linutronix.de, andi@lisas.de,
puwen@hygon.cn, mario.limonciello@amd.com, rui.zhang@intel.com,
gpiccoli@igalia.com, daniel.lezcano@linaro.org,
ananth.narayan@amd.com, gautham.shenoy@amd.com,
Calvin Ong <calvin.ong@amd.com>,
stable@vger.kernel.org, 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 10:17:05 +0200 [thread overview]
Message-ID: <YywaAcTdLSuDlRfl@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <YytqfVUCWfv0XyZO@zn.tnic>
On Wed, Sep 21, 2022 at 09:48:13PM +0200, Borislav Petkov wrote:
> On Wed, Sep 21, 2022 at 05:00:35PM +0200, Peter Zijlstra wrote:
> > On Wed, Sep 21, 2022 at 12:06:38PM +0530, K Prateek Nayak wrote:
> > > Processors based on the Zen microarchitecture support IOPORT based deeper
> > > C-states.
> >
> > I've just gotta ask; why the heck are you using IO port based idle
> > states in 2022 ?!?! You have have MWAIT, right?
>
> They have both. And both is Intel technology. And as I'm sure you
> know AMD can't do their own thing - they kinda have to follow Intel.
> Unfortunately.
>
> Are you saying modern Intel chipsets don't do IO-based C-states anymore?
I've no idea what they do, but Linux exclusively uses MWAIT on Intel as
per intel_idle.c.
MWAIT also cuts down on IPIs because it wakes from the TIF write.
next prev parent reply other threads:[~2022-09-22 8:18 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 [this message]
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
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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