100% cpu with every scroll in LibreOffice

gust · February 23, 2022, 3:57pm

Although I would never put it past LibreOffice to be slow, if it’s worse after 4.1 upgrade you might want to make sure you’re not hitting the CPU frequency detection bug (adding xen-acpi-processor kernel module is the remediation if you are).

github.com/QubesOS/qubes-issues

Intel CPU Frequency Scaling Broken

opened 10:23PM - 12 Dec 18 UTC

sylentprofet

T: bug C: Xen P: major r4.1-buster-stable hardware support r4.1-bullseye-stable r4.1-dom0-stable needs diagnosis pr submitted r4.1-centos-stream8-cur-test r4.1-bookworm-stable r4.2-host-cur-test affects-4.1 affects-4.2

### Qubes OS version:  R4.0 ### Affected component(s): intel_pstate acpi-cpufreq xenpm --- ### Steps to reproduce the behavior:  Tested on: - Lenovo T480s - Lenovo X1 Carbon Gen. 6 - Huawei Matebook X Pro. All with Intel i7-8550U. Latest BIOS revisions for the respective systems as of Dec. 2018 Kernel: 4.19.2-3.pvops.qubes.x86_64. EFI install. In dom0, `sudo xenpm get-cpufreq-para` ### Expected behavior: The processor is rated at 1.8 GHz (4.0 turbo), so we would expect to see appropriate scaling in that range, available frequencies from 1800000 - 4000000. Further, we would expect to see `scaling_driver = intel_pstate`. ### Actual behavior: The CPU frequencies do not scale correctly. Why? Frequencies are pinned at 2 GHz max, 400 MHz min, across all cores. ``` # xenpm cpu-freq-para ... cpu id : 0 affected_cpus : 0 cpuinfo frequency : max [2001000] min [400000] cur [2001000] scaling_driver : acpi-cpufreq scaling_avail_gov : userspace performance powersave ondemand current_governor : ondemand ondemand specific : sampling_rate : max [10000000] min [10000] cur [20000] up_threshold : 80 scaling_avail_freq : 2001000 2000000 1900000 1800000 1700000 1500000 1400000 1300000 1200000 1100000 1000000 800000 700000 600000 500000 *400000 scaling frequency : max [2001000] min [400000] cur [400000] turbo mode : enabled ... ``` Confirmed with `watch -n1 "cat /proc/cpuinfo | grep \"[c]pu MHz\""` `xenpm set-scaling-maxfreq` and `-minfreq` have no effect. `xenpm get-cpufreq-states` shows 16 total/usable P-states. Changing the governor to `performance` has no effect. Default is `ondemand` `dmidecode` reports a max of 2 GHz on the Lenovos, and an apparently erroneous speed on the Huawei (~ 8 GHz). ``` # dmidecode | grep -i speed Speed: 2400 MT/s Configured Clock Speed: 2400 MT/s Speed: 2400 MT/s Configured Clock Speed: 2400 MT/s Speed: Unknown Speed: Unknown Speed: Unknown Max Speed: 2000 MHz Current Speed: 1800 MHz ``` The `scaling_driver` is legacy `acpi-cpufreq`. Interestingly, `intel_pstate` can be seen initializing during boot, but it does not take over handling anything. Attempting to `blacklist acpi-cpufreq` in `modprobe.d` has no effect. ``` # dmesg | grep pstate [ 5.067624] intel_pstate: Intel P-state driver initializing ``` `/sys/devices/system/cpu/intel_pstate/` contains the expected attributes, but as mentioned in the "related issue" linked below, `no_turbo`, `num_pstates`, and `turbo_pct` error `Resource temporarily unavailable`. `/sys/devices/system/cpu/intel_pstate/status` always returns `off`, and does not respond to `echo "active" >`. This behavior has been tested with various kernel command line parameters, including `intel_pstate=force`, `intel_pstate=disabled`, `intel_pstate=no_hwp`, `intel_pstate=enable` with no change in performance aside from `../cpu/intel_pstate/` attributes disappearing when `no_hwp` or `disabled` were in effect. Also tried `processor.ignore_ppc=1`. Strangely, none of the appropriate attributes for `cpufreq` exist in `/sys/devices/system/cpu/cpu*/`. ``` # ls /sys/devices/system/cpu/cpu0/ acpi_cppc driver hotplug power topology cache firmware_node node0 subsystem uevent ``` `lsmod | grep cpufreq` shows no results, trying to `modprobe acpi-cpufreq` or `cpufreq-xen` returns errors. `xen_acpi_processor` is loaded. ``` # modprobe acpi-cpufreq modprobe: ERROR: could not insert 'acpi_cpufreq': No such device # modprobe cpufreq-xen modprobe: FATAL: Module cpufreq-xen not found in directory /lib/modules/4.19.2-3.pvops.qubes.x86_64 ``` `cpupower frequency-info` is completely unresponsive, with zero information available about the processor. ``` analyzing CPU 0: no or unknown cpufreq driver is active on this CPU CPUs which run at the same hardware frequency: Not Available CPUs which need to have their frequency coordinated by software: Not Available maximum transition latency: Cannot determine or is not supported. Not Available available cpufreq governors: Not Available Unable to determine current policy current CPU frequency: Unable to call hardware current CPU frequency: Unable to call to kernel boost state support: Supported: yes Active: yes ``` Though it shouldn't have any effect, testing was attempted with `smt=on` and `off`, and `Hyperthreading` enabled/disabled in the BIOS appropriately. Testing was also performed while toggling various BIOS settings. - enable/disable `Intel SpeedStep` - power settings at `Maximum Performance` vs. `Balanced` It does not appear to be a thermal throttling issue, with idle ~ 37*C and under load ~60*C observed consistently. `tlp` was tested with no effect on the frequency scaling, regardless of being enabled or disabled. `tlp-stat` yields minimal additional info, with what seems to be an outdated recommendation for the Lenovos to install `tp-smapi kernel modules`, that are in fact deprecated in favor of `thinkpad_acpi`, which appears to be active on the Thinkpads. ``` dmesg | grep thinkpad [ 19.589434] thinkpad_acpi: ThinkPad ACPI Extras v0.26 [ 19.589439] thinkpad_acpi: http://ibm-acpi.sf.net/ [ 19.589440] thinkpad_acpi: ThinkPad BIOS N22ET50W (1.27 ), EC unknown [ 19.589441] thinkpad_acpi: Lenovo ThinkPad T480s, model 20L7CTO1WW [ 19.591883] thinkpad_acpi: radio switch found; radios are enabled [ 19.591898] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver [ 19.591899] thinkpad_acpi: Disabling thinkpad-acpi brightness events by default... [ 19.612278] thinkpad_acpi: rfkill switch tpacpi_wwan_sw: radio is unblocked [ 19.643468] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one [ 19.674512] thinkpad_acpi: battery 1 registered (start 0, stop 100) [ 19.674576] input: ThinkPad Extra Buttons as /devices/platform/thinkpad_acpi/ ``` `thermald` is not loaded. ### General notes: https://www.kernel.org/doc/html/v4.12/admin-guide/pm/intel_pstate.html - This link suggests removing `irqbalance` but I'm skeptical. https://askubuntu.com/questions/1067866/ubuntu-18-04-steam-games-frame-rate-drop/1073353#1073353?newreg=c7c120f373da4effb7317104571cd573 - https://cateee.net/lkddb/web-lkddb/XEN_ACPI_PROCESSOR.html Regarding xen_acpi_processor: "It also registers itself as the SMM so that other drivers (such as ACPI cpufreq scaling driver) will not load." How could `lsmod` report `xen_acpi_processor` as loaded but `xenpm` shows the scaling driver `acpi-cpufreq` ? This might make sense as to the missing `/sys/devices/.../cpufreq` entries. - The following exchange is dubious at best, the final post gets down to the point of disabling intel microcode. They also suggest the use of `msr-tools`, but that really shouldn't be necessary. https://bbs.archlinux.org/viewtopic.php?id=231077 - This is good work, but in my opinion, running a script every few seconds in dom0 isn't a legitimate fix. https://github.com/erpalma/lenovo-throttling-fix --- ### Related issues: https://github.com/QubesOS/qubes-issues/issues/4491 https://github.com/QubesOS/qubes-issues/issues/450