This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification-needed- bionic' to 'verification-done-bionic'. If the problem still exists, change the tag 'verification-needed-bionic' to 'verification-failed- bionic'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed. Thank you! ** Tags added: verification-needed-bionic -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1790602 Title: Ubuntu18.04.1: cpuidle: powernv: Fix promotion from snooze if next state disabled (performance) Status in The Ubuntu-power-systems project: New Status in linux package in Ubuntu: New Status in linux source package in Bionic: Fix Committed Bug description: == Comment: #0 - Michael Ranweiler <mranw...@us.ibm.com> - 2018-09-04 00:50:14 == The CPUs remain in snooze state on an idle system when only the shallow states disabled resulting in increased power consumption. The commit 78eaa10f027c ("cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle state") introduced a timeout for the snooze idle state so that it could be eventually be promoted to a deeper idle state. The snooze timeout value is static and set to the target residency of the next idle state, which would train the cpuidle governor to pick the next idle state eventually. The unfortunate side-effect of this is that if the next idle state(s) is disabled, the CPU will forever remain in snooze, despite the fact that the system is completely idle, and other deeper idle states are available. This patch fixes the issue by dynamically setting the snooze timeout to the target residency of the next enabled state on the device. Before Patch: POWER8 : Only nap disabled. $ cpupower monitor sleep 30 sleep took 30.01297 seconds and exited with status 0 |Idle_Stats PKG |CORE|CPU | snoo | Nap | Fast 0| 8| 0| 96.41| 0.00| 0.00 0| 8| 1| 96.43| 0.00| 0.00 0| 8| 2| 96.47| 0.00| 0.00 0| 8| 3| 96.35| 0.00| 0.00 0| 8| 4| 96.37| 0.00| 0.00 0| 8| 5| 96.37| 0.00| 0.00 0| 8| 6| 96.47| 0.00| 0.00 0| 8| 7| 96.47| 0.00| 0.00 POWER9: Shallow states (stop0lite, stop1lite, stop2lite, stop0, stop1, stop2) disabled: $ cpupower monitor sleep 30 sleep took 30.05033 seconds and exited with status 0 |Idle_Stats PKG |CORE|CPU | snoo | stop | stop | stop | stop | stop | stop | stop | stop 0| 16| 0| 89.79| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00 0| 16| 1| 90.12| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00 0| 16| 2| 90.21| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00 0| 16| 3| 90.29| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00 After Patch: POWER8 : Only nap disabled. $ cpupower monitor sleep 30 sleep took 30.01200 seconds and exited with status 0 |Idle_Stats PKG |CORE|CPU | snoo | Nap | Fast 0| 8| 0| 16.58| 0.00| 77.21 0| 8| 1| 18.42| 0.00| 75.38 0| 8| 2| 4.70| 0.00| 94.09 0| 8| 3| 17.06| 0.00| 81.73 0| 8| 4| 3.06| 0.00| 95.73 0| 8| 5| 7.00| 0.00| 96.80 0| 8| 6| 1.00| 0.00| 98.79 0| 8| 7| 5.62| 0.00| 94.17 POWER9: Shallow states (stop0lite, stop1lite, stop2lite, stop0, stop1, stop2) disabled: $ cpupower monitor sleep 30 sleep took 30.02110 seconds and exited with status 0 |Idle_Stats PKG |CORE|CPU | snoo | stop | stop | stop | stop | stop | stop | stop | stop 0| 0| 0| 0.69| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 9.39| 89.70 0| 0| 1| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.05| 93.21 0| 0| 2| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 89.93 0| 0| 3| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 0.00| 93.26 This fix (commit 0a4ec6aa035a "cpuidle: powernv: Fix promotion from snooze if next state disabled") is in the -next branch of the powerpc tree and upstream:https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/cpuidle/cpuidle-powernv.c?id=0a4ec6aa035a52c422eceb2ed51ed88392a3d6c2 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1790602/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
