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From: Jack Allister <jalliste@amazon.com>
To: <dave.hansen@intel.com>
Cc: <bp@alien8.de>, <dave.hansen@linux.intel.com>,
	<hdegoede@redhat.com>, <hpa@zytor.com>, <jalliste@amazon.com>,
	<juew@amazon.com>, <len.brown@intel.com>,
	<linux-kernel@vger.kernel.org>, <mingo@redhat.com>,
	<pdurrant@amazon.com>, <peterz@infradead.org>,
	<rafael.j.wysocki@intel.com>, <rafael@kernel.org>,
	<tglx@linutronix.de>, <usama.arif@bytedance.com>,
	<x86@kernel.org>
Subject: Re: [PATCH] x86: intel_epb: Add earlyparam option to keep bias at performance
Date: Tue, 5 Dec 2023 10:23:02 +0000	[thread overview]
Message-ID: <20231205102302.58434-1-jalliste@amazon.com> (raw)
In-Reply-To: <c1e8e8cb-f792-4dcc-a72f-fbebe4476a1b@intel.com>

> This is fundamentally a hack.

I do not totally agree that this is a hack, the setting of it to the
ENERGY_PERF_BIAS_NORMAL is an equivalent workaround which is used for
systems where the platform firmware has not configured it as expected
for laptops etc. and that is already present.

> It sounds like you want the system default to be at
> ENERGY_PERF_BIAS_PERFORMANCE.  You also mentioned that this was done "on
> kernel boot".  How did you do that, exactly?  Shouldn't that "on kernel
> boot" action be reflected over here rather than introducing another
> command-line parameter?

As Paul has mentioned, we perform live-updates of the host kernel running
on servers. This is done while virtual machines are still running so that
there is no perceived downtime for the guest/customer. This requires a
kexec into the new kernel and there are specific areas such as PCI device
enumeration which can take a substantial amount of time in it's current
form and can be perceived as downtime while the kernel is loading.

> Shouldn't that "on kernel
> boot" action be reflected over here rather than introducing another
> command-line parameter?

A kernel parameter may not be the most elegant solution, would a proposal
for a kernel build configuration be a bit more suitable?

  parent reply	other threads:[~2023-12-05 10:23 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-12-04 17:28 [PATCH] x86: intel_epb: Add earlyparam option to keep bias at performance Jack Allister
2023-12-04 17:44 ` Dave Hansen
2023-12-05  9:00   ` Durrant, Paul
2023-12-05 12:00     ` David Woodhouse
2023-12-05 12:12       ` Rafael J. Wysocki
2023-12-05 12:15         ` David Woodhouse
2023-12-05 12:31           ` Rafael J. Wysocki
2023-12-05 12:32             ` David Woodhouse
2023-12-05 12:43               ` Rafael J. Wysocki
2023-12-05 15:19         ` Dave Hansen
2023-12-05 15:27           ` Dave Hansen
2023-12-05 10:23   ` Jack Allister [this message]
2023-12-05 12:48 ` Rafael J. Wysocki
2023-12-05 13:13   ` Jack Allister
2023-12-05 13:23     ` [PATCH v3] " Jack Allister
2023-12-05 15:26       ` Dave Hansen
2023-12-05 13:30     ` [PATCH] " Rafael J. Wysocki
2023-12-05 15:14       ` [PATCH v4] " Jack Allister
2023-12-05 16:17         ` Dave Hansen
2024-01-02 14:46           ` Jack Allister
2024-01-02 15:09             ` Dave Hansen
2024-01-03 14:46               ` [PATCH v5] " Jack Allister
2024-01-03 15:17                 ` Dave Hansen
2024-01-04  9:05                   ` [PATCH v6] " Jack Allister
2024-01-04  9:22                     ` Durrant, Paul
2024-01-03 15:18                 ` [External] [PATCH v5] " Usama Arif
2024-01-04  9:00                   ` Jack Allister

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