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From: Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com>
To: rafael@kernel.org
Cc: Perry.Yuan@amd.com, Xiaojian.Du@amd.com,
	alexander.deucher@amd.com, bp@alien8.de, deepak.sharma@amd.com,
	li.meng@amd.com, linux-acpi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-pm@vger.kernel.org, mario.limonciello@amd.com,
	nathan.fontenot@amd.com, oleksandr@natalenko.name,
	rafael.j.wysocki@intel.com, ray.huang@amd.com,
	shimmer.huang@amd.com, skhan@linuxfoundation.org,
	viresh.kumar@linaro.org, x86@kernel.org,
	Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com>
Subject: [PATCH] [PATCH] amd_pstate: fix erroneous highest_perf value on some CPUs
Date: Mon, 19 Feb 2024 00:10:31 +0800	[thread overview]
Message-ID: <20240218161435.38312-2-lucasleeeeeeeee@gmail.com> (raw)
In-Reply-To: <20240218161435.38312-1-lucasleeeeeeeee@gmail.com>

On a Ryzen 7840HS the highest_perf value is 196, not 166 as AMD assumed.
This leads to the advertised max clock speed to only be 4.35ghz instead of 5.14ghz , leading to a large degradation in performance.

Fix the broken assumption and revert back to the old logic for getting highest_perf.

TEST:
Geekbench 6 Before Patch:
Single Core:	2325 (-22%)!
Multi Core:	11335 (-10%)

Geekbench 6 AFTER Patch:
Single Core:	2635
Multi Core:	12487

Signed-off-by: Lucas Lee Jing Yi <lucasleeeeeeeee@gmail.com>
---
 drivers/cpufreq/amd-pstate.c | 22 ++++++++++------------
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 08e112444c27..54df68773620 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -50,7 +50,6 @@
 
 #define AMD_PSTATE_TRANSITION_LATENCY	20000
 #define AMD_PSTATE_TRANSITION_DELAY	1000
-#define AMD_PSTATE_PREFCORE_THRESHOLD	166
 
 /*
  * TODO: We need more time to fine tune processors with shared memory solution
@@ -299,15 +298,12 @@ static int pstate_init_perf(struct amd_cpudata *cpudata)
 				     &cap1);
 	if (ret)
 		return ret;
-
-	/* For platforms that do not support the preferred core feature, the
-	 * highest_pef may be configured with 166 or 255, to avoid max frequency
-	 * calculated wrongly. we take the AMD_CPPC_HIGHEST_PERF(cap1) value as
-	 * the default max perf.
+ 
+	/* Some CPUs have different highest_perf from others, it is safer 
+	 * to read it than to assume some erroneous value, leading to performance issues.
 	 */
-	if (cpudata->hw_prefcore)
-		highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD;
-	else
+	highest_perf = amd_get_highest_perf();
+	if(highest_perf > AMD_CPPC_HIGHEST_PERF(cap1))
 		highest_perf = AMD_CPPC_HIGHEST_PERF(cap1);
 
 	WRITE_ONCE(cpudata->highest_perf, highest_perf);
@@ -329,9 +325,11 @@ static int cppc_init_perf(struct amd_cpudata *cpudata)
 	if (ret)
 		return ret;
 
-	if (cpudata->hw_prefcore)
-		highest_perf = AMD_PSTATE_PREFCORE_THRESHOLD;
-	else
+	/* Some CPUs have different highest_perf from others, it is safer 
+	 * to read it than to assume some erroneous value, leading to performance issues.
+	 */
+	highest_perf = amd_get_highest_perf();
+	if(highest_perf > cppc_perf.highest_perf)
 		highest_perf = cppc_perf.highest_perf;
 
 	WRITE_ONCE(cpudata->highest_perf, highest_perf);
-- 
2.43.2


  reply	other threads:[~2024-02-18 16:15 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-01-19  9:04 [PATCH V14 0/7] amd-pstate preferred core Meng Li
2024-01-19  9:04 ` [PATCH V14 1/7] x86: Drop CPU_SUP_INTEL from SCHED_MC_PRIO for the expansion Meng Li
2024-01-19  9:04 ` [PATCH V14 2/7] ACPI: CPPC: Add get the highest performance cppc control Meng Li
2024-01-19  9:04 ` [PATCH V14 3/7] cpufreq: amd-pstate: Enable amd-pstate preferred core supporting Meng Li
2024-01-19  9:04 ` [PATCH V14 4/7] cpufreq: Add a notification message that the highest perf has changed Meng Li
2024-01-19  9:05 ` [PATCH V14 5/7] cpufreq: amd-pstate: Update amd-pstate preferred core ranking dynamically Meng Li
2024-01-19  9:05 ` [PATCH V14 6/7] Documentation: amd-pstate: introduce amd-pstate preferred core Meng Li
2024-01-19  9:05 ` [PATCH V14 7/7] Documentation: introduce amd-pstate preferrd core mode kernel command line options Meng Li
2024-01-29 15:18 ` [PATCH V14 0/7] amd-pstate preferred core Rafael J. Wysocki
2024-01-29 15:33   ` Borislav Petkov
2024-01-31 13:58     ` Rafael J. Wysocki
2024-02-18 16:10       ` Lucas Lee Jing Yi
2024-02-18 16:10         ` Lucas Lee Jing Yi [this message]
2024-02-20  7:23           ` [PATCH] [PATCH] amd_pstate: fix erroneous highest_perf value on some CPUs Meng, Li (Jassmine)
2024-02-20  9:02           ` Oleksandr Natalenko
2024-02-21 17:19             ` Lucas Lee Jing Yi
2024-02-21 17:19               ` Lucas Lee Jing Yi
2024-02-21 18:47                 ` Mario Limonciello
2024-02-19  1:02         ` [PATCH V14 0/7] amd-pstate preferred core Meng, Li (Jassmine)

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