CPU frequency is lower than it should be

[AlexandreTunstall]

The cpuinfo_cur_freq and scaling_cur_freq don't match, suggesting that the kernel is unable to control the CPU frequency. Note that cpuinfo_cur_freq is reported by the hardware and scaling_cur_freq is the last frequency the kernel requested the hardware to use.

$ cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_{cur,max}_freq
1000000
1500000
$ cat /sys/devices/system/cpu/cpufreq/policy0/scaling_{driver,governor,cur_freq}
cpufreq-dt
performance
1500000

The system isn't thermal throttling, since the temperature is well under the passive trip point.

$ cat /sys/class/thermal/thermal_zone0/temp
45945
$ cat /sys/class/thermal/thermal_zone0/trip_point_0_{temp,type}
75000
passive

I'm using Linux 6.4.0 from commit e5a381c51d624ffd8784db908a58ae227d0608a4 (from the JH7110_VisionFive2_upstream branch) and u-boot from release 2.10.4 of this repository since later versions don't fit into flash. I can't use a later release of u-boot because, at the moment, I can only boot from flash.

This kernel version includes the PMIC and CPU frequency patch sets, so I expect it to be able to control the CPU frequency. The kernel config can be found here. I've also tried explicitly enabling REGULATOR_AXP15060, but that didn't make a difference.

Is something missing from the kernel or u-boot to make this work?

[AlexandreTunstall]

I tried setting the governor to userspace and manually setting the CPU frequency. It seems that, for some reason, the system sets a lower frequency than intended for most frequencies.

scaling_cur_freq	cpuinfo_cur_freq
375000	333333
500000	500000
750000	500000
1500000	1000000

I can't test other frequencies at the moment, since these are all my current kernel allows.

I've updated the title to reflect this new finding.

[mmoll]

@AlexandreTunstall I'm seeing the same, but it seems to work with the 5.15 kernel coming with the Debian image (benchmarks with the same binaries also showing an appropriate speed difference), so I think this is some defect in the 6.x kernel tree.

[MichaelZhuxx]

The PLL0 is set to 1.0GHz. we will submit patch to fix this after this patchsets "Add PLL clocks driver and syscon for StarFive JH7110 SoC" is upstreamed.https://lwn.net/Articles/937299/

[misuzu]

Still an issue when using kernel from https://github.com/starfive-tech/linux/commit/64a6c57ec372c44d0f25416c9614657e274fccff

% dmesg | grep -i freq
[   14.305896] platform cpufreq-dt: deferred probe pending
[   33.101720] cpufreq: cpufreq_online: CPU0: Running at unlisted initial frequency: 1000000 KHz, changing to: 1500000 KHz
% sudo grep '' /sys/devices/system/cpu/cpufreq/policy0/*
/sys/devices/system/cpu/cpufreq/policy0/affected_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq:1000000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq:375000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency:4294967295
/sys/devices/system/cpu/cpufreq/policy0/related_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies:375000 500000 750000 1500000 
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors:performance schedutil 
/sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/scaling_driver:cpufreq-dt
/sys/devices/system/cpu/cpufreq/policy0/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq:375000
/sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed:<unsupported>
% sudo grep '' /sys/class/thermal/thermal_zone0/*       
/sys/class/thermal/thermal_zone0/available_policies:step_wise 
/sys/class/thermal/thermal_zone0/integral_cutoff:0
/sys/class/thermal/thermal_zone0/k_d:0
/sys/class/thermal/thermal_zone0/k_i:0
/sys/class/thermal/thermal_zone0/k_po:0
/sys/class/thermal/thermal_zone0/k_pu:0
/sys/class/thermal/thermal_zone0/mode:enabled
/sys/class/thermal/thermal_zone0/offset:0
/sys/class/thermal/thermal_zone0/policy:step_wise
grep: /sys/class/thermal/thermal_zone0/power: Is a directory
/sys/class/thermal/thermal_zone0/slope:1
grep: /sys/class/thermal/thermal_zone0/subsystem: Is a directory
/sys/class/thermal/thermal_zone0/sustainable_power:0
/sys/class/thermal/thermal_zone0/temp:60158
/sys/class/thermal/thermal_zone0/trip_point_0_hyst:2000
/sys/class/thermal/thermal_zone0/trip_point_0_temp:85000
/sys/class/thermal/thermal_zone0/trip_point_0_type:passive
/sys/class/thermal/thermal_zone0/trip_point_1_hyst:2000
/sys/class/thermal/thermal_zone0/trip_point_1_temp:100000
/sys/class/thermal/thermal_zone0/trip_point_1_type:critical
/sys/class/thermal/thermal_zone0/type:cpu-thermal
% uname -a 
Linux nixos 6.5.0-rc1 #1-NixOS SMP Tue Jan  1 00:00:00 UTC 1980 riscv64 GNU/Linux

[AlexandreTunstall]

I'm not sure whether this is good enough to be upstreamed to mainline, but I've come up with a patch that fixes the problem.

--- a/drivers/clk/starfive/clk-starfive-jh7110-sys.c
+++ b/drivers/clk/starfive/clk-starfive-jh7110-sys.c
@@ -407,12 +407,14 @@
    /* Use fixed factor clocks if can not get the PLL clocks from DTS */
    pllclk = clk_get(priv->dev, "pll0_out");
    if (IS_ERR(pllclk)) {
-       /* 24MHz -> 1000.0MHz */
+       /* 24MHz -> 1500.0MHz */
        priv->pll[0] = devm_clk_hw_register_fixed_factor(priv->dev, "pll0_out",
-                                "osc", 0, 125, 3);
+                                "osc", 0, 125, 2);
        if (IS_ERR(priv->pll[0]))
            return PTR_ERR(priv->pll[0]);
    } else {
+       if (clk_set_rate(pllclk, 1500000000))
+           dev_err(priv->dev, "set pll0 rate failed\n");
        clk_put(pllclk);
        priv->pll[0] = NULL;
    }

After building with the patch:

[root@nixos:~]# cat /sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq
1500000

[root@nixos:~]# uname -a
Linux nixos 6.5.0-rc1 #1-NixOS SMP Mon Jul 24 07:58:38 UTC 2023 riscv64 GNU/Linux

I'll leave this open until a fix is upstreamed.

[misuzu]

https://github.com/starfive-tech/linux/commit/67e8df01b875afd312a7d2ab77f56a62f39dd6d9 seems to fix it

% dmesg | grep -i freq
[    0.004481] Calibrating delay loop (skipped), value calculated using timer frequency.. 8.00 BogoMIPS (lpj=16000)
[   18.677004] platform cpufreq-dt: deferred probe pending
% sudo grep '' /sys/devices/system/cpu/cpufreq/policy0/*
/sys/devices/system/cpu/cpufreq/policy0/affected_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_cur_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq:375000
/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_transition_latency:4294967295
/sys/devices/system/cpu/cpufreq/policy0/related_cpus:0 1 2 3
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies:375000 500000 750000 1500000 
/sys/devices/system/cpu/cpufreq/policy0/scaling_available_governors:performance schedutil 
/sys/devices/system/cpu/cpufreq/policy0/scaling_cur_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/scaling_driver:cpufreq-dt
/sys/devices/system/cpu/cpufreq/policy0/scaling_governor:performance
/sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq:1500000
/sys/devices/system/cpu/cpufreq/policy0/scaling_min_freq:375000
/sys/devices/system/cpu/cpufreq/policy0/scaling_setspeed:<unsupported>
% sudo grep '' /sys/class/thermal/thermal_zone0/*       
/sys/class/thermal/thermal_zone0/available_policies:step_wise 
/sys/class/thermal/thermal_zone0/integral_cutoff:0
/sys/class/thermal/thermal_zone0/k_d:0
/sys/class/thermal/thermal_zone0/k_i:0
/sys/class/thermal/thermal_zone0/k_po:0
/sys/class/thermal/thermal_zone0/k_pu:0
/sys/class/thermal/thermal_zone0/mode:enabled
/sys/class/thermal/thermal_zone0/offset:0
/sys/class/thermal/thermal_zone0/policy:step_wise
grep: /sys/class/thermal/thermal_zone0/power: Is a directory
/sys/class/thermal/thermal_zone0/slope:1
grep: /sys/class/thermal/thermal_zone0/subsystem: Is a directory
/sys/class/thermal/thermal_zone0/sustainable_power:0
/sys/class/thermal/thermal_zone0/temp:58302
/sys/class/thermal/thermal_zone0/trip_point_0_hyst:2000
/sys/class/thermal/thermal_zone0/trip_point_0_temp:85000
/sys/class/thermal/thermal_zone0/trip_point_0_type:passive
/sys/class/thermal/thermal_zone0/trip_point_1_hyst:2000
/sys/class/thermal/thermal_zone0/trip_point_1_temp:100000
/sys/class/thermal/thermal_zone0/trip_point_1_type:critical
/sys/class/thermal/thermal_zone0/type:cpu-thermal
% 7z b

7-Zip 17.05 : Copyright (c) 1999-2021 Igor Pavlov : 2017-08-28
p7zip Version 17.05 (locale=en_US.UTF-8,Utf16=on,HugeFiles=on,64 bits,4 CPUs LE)

LE
CPU Freq: 64000000 64000000 64000000 64000000 - - - - 2048000000

RAM size:    7940 MB,  # CPU hardware threads:   4
RAM usage:    882 MB,  # Benchmark threads:      4

                       Compressing  |                  Decompressing
Dict     Speed Usage    R/U Rating  |      Speed Usage    R/U Rating
         KiB/s     %   MIPS   MIPS  |      KiB/s     %   MIPS   MIPS

22:       2565   333    750   2496  |      62672   398   1344   5347
23:       2487   339    747   2535  |      61326   398   1334   5306
24:       2456   349    756   2642  |      59227   393   1323   5199
25:       2295   340    770   2621  |      58304   398   1305   5189
----------------------------------  | ------------------------------
Avr:             340    756   2573  |              397   1327   5260
Tot:             368   1041   3917
% uname -a 
Linux nixos 6.5.0-rc1 #1-NixOS SMP Tue Jan  1 00:00:00 UTC 1980 riscv64 GNU/Linux

[MichaelZhuxx]

Yup, we have sent out a fixes patch https://lore.kernel.org/all/20230811033631.160912-1-xingyu.wu@starfivetech.com/

[davidlt]

I noticed this didn't receive any updates. Was this forgotten?

[AlexandreTunstall]

Was this forgotten?

The fix doesn't appear to be in mainline yet, so this remains open.