throttled Thinkpad P1 throttling sometimes!?

I'm using dual boot Thinkpad P1 (Ubuntu 16.04, Windows 10).

While my P1 works great without throttling on Windows 10, it suffers from CPU throttling on Ubuntu 16.04. So I found this github project it works great. My P1 (i7-8750H) can reach all core 3.3GHz while stress testing on windows and ubuntu.

However, on ubuntu, sometimes all six CPU clock is stuck at the base CPU clock which is around 900MHz. It is resolved if I unplug the power cable from the thinkpad and connect it again. This behavior is quite annoying. Any clue? Thank you for great project!

Jul 04 '19 10:07 omnibusor

Hmm... Thermald, tlp or other power management software installed?

Jul 04 '19 10:07 erpalma

It's vanilla ubuntu 16.04.06, thermald is removed and tlp is not installed... I changed power management settings on BIOS but no luck.

Jul 05 '19 00:07 omnibusor

from the description it could have something to do with the switch from battery to ac mode. maybe throttled was in battery mode which may be configured to do such things (check your config). maybe there is some kind of bug in throttled getting fixed when switching the profile. maybe it is not related to throttled at all.

Jul 06 '19 08:07 DEvil0000

@DEvil0000 Bingo. I unplug the AC power, discharged the battery to 30%. Then, I connect the AC power and see if the throttling occurs. It does not happen at all...

This happens if the battery is fully charged. It seems that my Thinkpad uses battery power if it is fully charged even if AC power is connected.

I will try to find out how to force AC power to always be used when connecting AC. Thanks

Jul 08 '19 00:07 omnibusor

Is your sysFs path configured correct (depends on the kernel e.g. /sys/class/power_supply/AC*/online)? what does your sysfs report when its throttled? what is reported by upower -i /org/freedesktop/UPower/devices/line_power_AC when throttled? what does upower -i /org/freedesktop/UPower/devices/battery_BAT0 report when throttled? You could also try method dbus instead of polling - then check dbus path /org/freedesktop/UPower/devices/line_power_AC which is quite the same as using upower I think.

@erpalma the script does not print power source changes between ac and bat right? or what is active/detected at the moment?

Jul 08 '19 08:07 DEvil0000

cat /sys/class/power_supply/AC*/online always shows 1 when AC connected, but throttling exists.
While it is throttling, there is no CPU throttling related messages In /var/log/kern.log.
/org does not exist on my machine ( Ubuntu 16.04). Maybe it is Unity-based?

Do I need to upgrade my machine to Ubuntu 18.04?

[EDIT] when this annoying throttling happens, all six CPU clock is stuck at the base CPU clock (around 900MHz) while stress testing (i.e., stress -c 12)

Jul 09 '19 00:07 omnibusor

this is not a FS path and may depend on your setup.

The first point should be the most important.

You can try to get more information when starting the script with --monitor or --debug. Most likely there is some other software limiting you just in this case.

Jul 09 '19 14:07 DEvil0000

sudo ./lenovo_fix.py --monitor or --debug always show [AC] and throttling still exists.

BTW, thanks for helping me out. I will share the result if I handle this shit

Jul 10 '19 00:07 omnibusor

Kernel version? This is strange: "all six CPU clock is stuck at the base CPU clock". Can you post the output of grep -R '' /sys/devices/system/cpu/cpu0/cpufreq/ when the CPU is stuck at 900MHz please?

Jul 12 '19 08:07 erpalma

low cpu frequency while stress testing.. (i.e., stress -c 12)
uname -a : Linux P1 4.15.0-54-generic #58~16.04.1-Ubuntu SMP Mon Jun 24 13:21:41 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

Jul 15 '19 07:07 omnibusor

As described above, this problem seems to be related to the battery. this throttling occurs if the battery is fully charged.

Jul 15 '19 07:07 omnibusor

whats your load on the cpu? thats strange. is the CPU maybe going for max efficiency - this could be around 900MHz for all cores used.

Jul 15 '19 07:07 DEvil0000

Your CPU is > 50% in halt state! There is something that is forcing your CPU in C1, do you have intel_powerclamp module loaded?

Jul 15 '19 09:07 erpalma

@erpalma there are registers holding a table with max power or max multiplier for full load on x cores. this may also be involved here. And the C0/C1 confuses me since C0 reads like 99.8% and C1 56%

Jul 15 '19 09:07 DEvil0000

@erpalma I will check the intel_powerclamp tomorrow. @DEvil0000 the machine can reach all core 3.3GHz under some condition. First, if the battery is not fully charged and the AC adapter is connected. Second, when the battery is fully charged, I unplug the AC adapter and plug it again, the machine can reach all core 3.3GHz for a while, but it is throttling after 2 or 3 minutes.

Jul 15 '19 10:07 omnibusor

found a solution in the following link.

https://forums.lenovo.com/t5/ThinkPad-P-and-W-Series-Mobile/Thinkpad-P1-plugged-in-not-charging/td-p/4370761

the representative instructed me to shutdown the Thinkpad.
turn it upside down and look for a small pin-hole near the middle of the base.
I then used a paper clip, pressed it into this hole and held it for 30 seconds.

No throttling at all, it completely disappears and lenovo_fix program works great, the machine can reach all core 3.4GHz!!

Jul 16 '19 01:07 omnibusor

So basically you just reset the bios?

Jul 16 '19 07:07 erpalma

I think this hole is related with some reset stuff, but not sure it reset the bios. However, reset the bios configuration (i.e., load default configuration in the bios), did not resolve the problem.

Jul 16 '19 11:07 omnibusor

However, reset the bios configuration (i.e., load default configuration in the bios), did not resolve the problem.

What? Really? So I guess that the hole is also resetting some stuff related to the EC, nice to know!

Jul 16 '19 16:07 erpalma