More observations: The problem does not happen if I disable Intel speed-step in BIOS. In this case, the CPU frequency of all cores goes to 2998 MHz whenever under load, and stays stable regardless of how long the load is applied.
The problem still happens even if intel_pstate=disable is passed to the kernel on boot. I tried forcing the CPU to its max frequency by using userspace governor and it worked only under idle load (freq ~3.9 GHz). As soon as multi-core load was applied, the CPU frequency dropped to ~1.6 GHz and went back to ~3.9 GHz only when the load was over. I observed a similar pattern when trying to force CPU only to 2.8 GHz - it still slowed down to 1.6 GHz under load, even though temperature should not be a problem in this case. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1797802 Title: Erratic behavior of intel pstate CPU frequency control To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1797802/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
