kernel-packages team mailing list archive

[Doug Smythies <1497520@xxxxxxxxxxxxxxxxxx>]

For your Intel(R) Core(TM) i5-2520M CPU @ 2.50GHz processor, what is the
normal minimum pstate? I ask because I have only seen on battery power
resume from suspend issues that are related to Clock Modulation becoming
enabled. i.e. I am wondering if 800MHz is a normal minimum frequency or
below the normal minimum.

One way, would be to do:

cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_min_freq
1600000
1600000
1600000
1600000
1600000
1600000
1600000
1600000

and you can see that on my computer ( Intel(R) Core(TM) i7-2600K CPU @
3.40GHz ), the minimum pstate is 16.

I'm not sure yet if our issues are related, but on my computer, I also
am seeing odd stuff on resume from suspend (I didn't used to), but my
CPU frequencies are not stuck low, but rather never go below pstate 24,
even though the driver is asking for lower. I also get  the same lack of
restoring the proper governor on all the CPUs except CPU 0 (and note
that for an S3 suspend CPU 0 is the one that never goes off line).

Example (no load):

pstate being asked for:

# rdmsr --bitfield 15:8 -d -a 0x199
16
16
16
16
16
16
16
16

pstate that I am getting:

# rdmsr --bitfield 15:8 -d -a 0x198
24
24
24
24
24
24
24
24

CPU freqs:

# grep MHz /proc/cpuinfo
cpu MHz         : 2400.054
cpu MHz         : 2399.921
cpu MHz         : 2399.921
cpu MHz         : 2399.921
cpu MHz         : 2399.789
cpu MHz         : 2399.789
cpu MHz         : 2399.921
cpu MHz         : 2399.921

-- 
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/1497520

Title:
  Slow performance after resuming from/on battery (CPUs do not scale
  above 800MHz) with intel_pstate

Status in linux package in Ubuntu:
  Incomplete

Bug description:
  I have noticed slow performance after resuming from STR on battery.

  I can not trigger this always, but it seems to be related to
  suspending and resuming while on battery.

  The CPU scaling governors look like this then:

  % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
  powersave
  performance
  performance
  performance

  % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_driver 
  intel_pstate
  intel_pstate
  intel_pstate
  intel_pstate

  % cat /sys/devices/system/cpu/cpu*/cpufreq/scaling_max_freq
  3200000
  3200000
  3200000
  3200000

  When watching the current CPU frequencies, it can be seen that they
  don't go above 800000 ('watch grep \"cpu MHz\" /proc/cpuinfo').

  I cannot see why they are limited to 800000.

  It looks like https://bugzilla.kernel.org/show_bug.cgi?id=61241, but
  /sys/devices/system/cpu/intel_pstate/max_perf_pct is at 100.

  Just writing the same setting for cpu0 again fixes it, and all CPUs
  will be scaled above 800MHz again:

  % echo powersave | sudo tee
  /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

  ProblemType: Bug
  DistroRelease: Ubuntu 15.04
  Package: linux-image-3.19.0-28-generic 3.19.0-28.30
  ProcVersionSignature: Ubuntu 3.19.0-28.30-generic 3.19.8-ckt5
  Uname: Linux 3.19.0-28-generic x86_64
  ApportVersion: 2.17.2-0ubuntu1.4
  Architecture: amd64
  CurrentDesktop: Unity
  Date: Sat Sep 19 10:39:02 2015
  HibernationDevice: RESUME=UUID=d39463f5-889e-42ba-a729-f3f442f0c8dd
  InstallationDate: Installed on 2012-05-28 (1208 days ago)
  InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
  MachineType: LENOVO 42992PG
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-28-generic root=/dev/mapper/vg0-rootlv ro quiet splash
  RelatedPackageVersions:
   linux-restricted-modules-3.19.0-28-generic N/A
   linux-backports-modules-3.19.0-28-generic  N/A
   linux-firmware                             1.143.3
  SourcePackage: linux
  UpgradeStatus: Upgraded to vivid on 2015-05-14 (127 days ago)
  dmi.bios.date: 05/14/2015
  dmi.bios.vendor: LENOVO
  dmi.bios.version: 8DET70WW (1.40 )
  dmi.board.asset.tag: Not Available
  dmi.board.name: 42992PG
  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:bvr8DET70WW(1.40):bd05/14/2015:svnLENOVO:pn42992PG:pvrThinkPadX220Tablet:rvnLENOVO:rn42992PG:rvrNotAvailable:cvnLENOVO:ct10:cvrNotAvailable:
  dmi.product.name: 42992PG
  dmi.product.version: ThinkPad X220 Tablet
  dmi.sys.vendor: LENOVO

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1497520/+subscriptions