Kernel 3.15 contains some intel_pstate changes that should address the issues I raised in post 16 above.
For Ubuntu one concern is: For the 250 Hz kernel the default sample rate will result in an actual different sample rate, and thus the response curve is a little different than for the 1000 Hz kernel. The desire is to have the default sample rate be 12 milliseconds instead of 10 (3 jiffies for 250 Hertz and 10 jiffies for 1000 Hz). This change is on the to-do list. This is probably a minor issue. For this change: "intel_pstate: add sample time scaling" I have a concern (and a ton of evidence to support it) that often, but very dependent on periodic workloads, the deferrable timer is delayed when it is not expected to be delayed, and sometimes by a huge amount (4 seconds). The result can be lower than expected CPU frequencies, because new the scale down code kicks in when it shouldn't. -- 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/1188647 Title: Please change intel_pstate default to disable Status in “linux” package in Ubuntu: Fix Released Bug description: 3.9 introduced a new default governor on SandyBridge CPUs called INTEL_PSTATE which, when built in and enabled (the default), removes all other governors (like our usual default, ondemand). 3.10 extended this to Ivybridge generation CPUs. In theory, this isn't an awful thing, as the new Intel pstate governor should be higher performance and give better power savings. In theory. In practice, it drives my CPUs to max frequency nearly constantly, spins my fans like mad and, somehow, does all of this while also eating enough CPU time in kernel threads to make my machine choppy, unresponsive, and unable to do simple things like play videos when I get off work. Therefore, I propose that we, for now, toggle intel_pstate to disable by default (I am using intel_pstate=disable on my command line right now, with great success), so it's still built in, and people can play with it, but it's off by default. ProblemType: Bug DistroRelease: Ubuntu 13.10 Package: linux-image-3.9.0-4-generic 3.9.0-4.9 ProcVersionSignature: Ubuntu 3.9.0-4.9-generic 3.9.4 Uname: Linux 3.9.0-4-generic x86_64 ApportVersion: 2.10.2-0ubuntu1 Architecture: amd64 AudioDevicesInUse: USER PID ACCESS COMMAND /dev/snd/controlC0: adconrad 2574 F.... pulseaudio CurrentDmesg: [ 30.633035] init: plymouth-stop pre-start process (2079) terminated with status 1 [ 36.086916] br0: port 1(eth0) entered forwarding state Date: Fri Jun 7 08:48:56 2013 HibernationDevice: RESUME=UUID=73040efa-baec-458a-8307-3bca07b26c3c InstallationDate: Installed on 2012-12-09 (179 days ago) InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Alpha amd64 (20121209) MachineType: LENOVO 4173LPB MarkForUpload: True ProcFB: 0 inteldrmfb ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.9.0-4-generic root=UUID=2222aad5-ef31-4428-973f-71740fc7cb6a ro intel_pstate=disable quiet splash vt.handoff=7 RelatedPackageVersions: linux-restricted-modules-3.9.0-4-generic N/A linux-backports-modules-3.9.0-4-generic N/A linux-firmware 1.109 SourcePackage: linux UpgradeStatus: No upgrade log present (probably fresh install) dmi.bios.date: 09/13/2012 dmi.bios.vendor: LENOVO dmi.bios.version: 8CET55WW (1.35 ) dmi.board.asset.tag: Not Available dmi.board.name: 4173LPB dmi.board.vendor: LENOVO dmi.board.version: Not Available dmi.chassis.asset.tag: No Asset Information dmi.chassis.type: 10 dmi.chassis.vendor: LENOVO dmi.chassis.version: Not Available dmi.modalias: dmi:bvnLENOVO:bvr8CET55WW(1.35):bd09/13/2012:svnLENOVO:pn4173LPB:pvrThinkPadT420s:rvnLENOVO:rn4173LPB:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable: dmi.product.name: 4173LPB dmi.product.version: ThinkPad T420s dmi.sys.vendor: LENOVO To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1188647/+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
