54 lines
2.1 KiB
Diff
54 lines
2.1 KiB
Diff
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From 1d5cc90283f9de0c4cc996a2f3e6ba0306c1f14d Mon Sep 17 00:00:00 2001
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From: Steven Barrett <steven@liquorix.net>
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Date: Wed, 15 Jan 2020 20:43:56 -0600
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Subject: ZEN: intel-pstate: Implement "enable" parameter
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If intel-pstate is compiled into the kernel, it will preempt the loading
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of acpi-cpufreq so you can take advantage of hardware p-states without
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any friction.
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However, intel-pstate is not completely superior to cpufreq's ondemand
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for one reason. There's no concept of an up_threshold property.
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In ondemand, up_threshold essentially reduces the maximum utilization to
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compare against, allowing you to hit max frequencies and turbo boost
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from a much lower core utilization.
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With intel-pstate, you have the concept of minimum and maximum
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performance, but no tunable that lets you define, maximum frequency
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means 50% core utilization. For just this oversight, there's reasons
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you may want ondemand.
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Lets support setting "enable" in kernel boot parameters. This lets
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kernel maintainers include "intel_pstate=disable" statically in the
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static boot parameters, but let users of the kernel override this
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selection.
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---
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Documentation/admin-guide/kernel-parameters.txt | 3 +++
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drivers/cpufreq/intel_pstate.c | 2 ++
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2 files changed, 5 insertions(+)
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--- a/Documentation/admin-guide/kernel-parameters.txt
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+++ b/Documentation/admin-guide/kernel-parameters.txt
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@@ -2237,6 +2237,9 @@
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disable
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Do not enable intel_pstate as the default
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scaling driver for the supported processors
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+ enable
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+ Enable intel_pstate in-case "disable" was passed
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+ previously in the kernel boot parameters
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active
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Use intel_pstate driver to bypass the scaling
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governors layer of cpufreq and provides it own
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--- a/drivers/cpufreq/intel_pstate.c
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+++ b/drivers/cpufreq/intel_pstate.c
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@@ -3524,6 +3524,8 @@ static int __init intel_pstate_setup(cha
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if (!strcmp(str, "disable"))
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no_load = 1;
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+ else if (!strcmp(str, "enable"))
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+ no_load = 0;
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else if (!strcmp(str, "active"))
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default_driver = &intel_pstate;
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else if (!strcmp(str, "passive"))
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