linux-kernel - [PATCH v5 6/7] cpufreq: amd-pstate: update pstate frequency transition delay time

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Date:   Mon, 15 Aug 2022 00:35:47 +0800
From:   Perry Yuan <Perry.Yuan@....com>
To:     <rafael.j.wysocki@...el.com>, <ray.huang@....com>,
        <viresh.kumar@...aro.org>
CC:     <Deepak.Sharma@....com>, <Mario.Limonciello@....com>,
        <Nathan.Fontenot@....com>, <Alexander.Deucher@....com>,
        <Jinzhou.Su@....com>, <Shimmer.Huang@....com>,
        <Xiaojian.Du@....com>, <Li.Meng@....com>,
        <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Perry Yuan <Perry.Yuan@....com>
Subject: [PATCH v5 6/7] cpufreq: amd-pstate: update pstate frequency transition delay time

Change the default transition latency to be 20ms that is more
reasonable transition delay for AMD processors in non-EPP driver mode.

Update transition delay time to 1ms, in the AMD CPU autonomous mode and
non-autonomous mode, CPPC firmware will decide frequency at 1ms timescale
based on the workload utilization.

Acked-by: Viresh Kumar <viresh.kumar@...aro.org>
Signed-off-by: Perry Yuan <Perry.Yuan@....com>
---
 drivers/cpufreq/amd-pstate.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index e40177d14310..9cb051d61422 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -41,8 +41,8 @@
 #include <asm/msr.h>
 #include "amd-pstate-trace.h"
 
-#define AMD_PSTATE_TRANSITION_LATENCY	0x20000
-#define AMD_PSTATE_TRANSITION_DELAY	500
+#define AMD_PSTATE_TRANSITION_LATENCY	20000
+#define AMD_PSTATE_TRANSITION_DELAY	1000
 
 /*
  * TODO: We need more time to fine tune processors with shared memory solution
-- 
2.34.1