linux-kernel - [PATCH] cpufreq: amd-pstate: Update policy->cur for adjust perf

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Message-ID: <20230518055819.71585-1-wyes.karny@amd.com>
Date:   Thu, 18 May 2023 05:58:19 +0000
From:   Wyes Karny <wyes.karny@....com>
To:     <ray.huang@....com>, <rafael@...nel.org>, <viresh.kumar@...aro.org>
CC:     <linux-pm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <gautham.shenoy@....com>, Wyes Karny <wyes.karny@....com>
Subject: [PATCH] cpufreq: amd-pstate: Update policy->cur for adjust perf

Driver should update policy->cur after updating the frequency.
Currently amd_pstate doesn't update policy->cur when `adjust_perf`
is used. Which causes /proc/cpuinfo to show wrong cpu frequency.
Fix this by updating policy->cur with correct frequency value in
adjust_perf function callback.

- Before the fix: (setting min freq to 1.5 MHz)

[root@amd]# cat /proc/cpuinfo | grep "cpu MHz" | sort | uniq --count
      1 cpu MHz         : 1777.016
      1 cpu MHz         : 1797.160
      1 cpu MHz         : 1797.270
    189 cpu MHz         : 400.000

- After the fix: (setting min freq to 1.5 MHz)

[root@amd]# cat /proc/cpuinfo | grep "cpu MHz" | sort | uniq --count
      1 cpu MHz         : 1753.353
      1 cpu MHz         : 1756.838
      1 cpu MHz         : 1776.466
      1 cpu MHz         : 1776.873
      1 cpu MHz         : 1777.308
      1 cpu MHz         : 1779.900
    183 cpu MHz         : 1805.231
      1 cpu MHz         : 1956.815
      1 cpu MHz         : 2246.203
      1 cpu MHz         : 2259.984

Fixes: 1d215f0319c2 ("cpufreq: amd-pstate: Add fast switch function for AMD P-State")

Signed-off-by: Wyes Karny <wyes.karny@....com>
---
 drivers/cpufreq/amd-pstate.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 5a3d4aa0f45a..736dab69ba1e 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -479,12 +479,14 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 				   unsigned long capacity)
 {
 	unsigned long max_perf, min_perf, des_perf,
-		      cap_perf, lowest_nonlinear_perf;
+		      cap_perf, lowest_nonlinear_perf, max_freq;
 	struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
 	struct amd_cpudata *cpudata = policy->driver_data;
+	unsigned int target_freq;
 
 	cap_perf = READ_ONCE(cpudata->highest_perf);
 	lowest_nonlinear_perf = READ_ONCE(cpudata->lowest_nonlinear_perf);
+	max_freq = READ_ONCE(cpudata->max_freq);
 
 	des_perf = cap_perf;
 	if (target_perf < capacity)
@@ -501,6 +503,10 @@ static void amd_pstate_adjust_perf(unsigned int cpu,
 	if (max_perf < min_perf)
 		max_perf = min_perf;
 
+	des_perf = clamp_t(unsigned long, des_perf, min_perf, max_perf);
+	target_freq = div_u64(des_perf * max_freq, max_perf);
+	policy->cur = target_freq;
+
 	amd_pstate_update(cpudata, min_perf, des_perf, max_perf, true,
 			policy->governor->flags);
 	cpufreq_cpu_put(policy);
-- 
2.34.1