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[Doug Smythies <1477171@xxxxxxxxxxxxxxxxxx>]

Isn't there another issue within this bug report? Why doesn't the acpi-
cpufreq frequency scaling driver support the higher available clock
frequencies?

Actually, maybe it does. Observe processor 3 from the cpuinfo listing:

processor	: 3
...
cpu MHz		: 2901.000

It is in turbo mode. 
Regardless of what other tools say, what does turbostat report for CPU frequencies when using the acpi-cpufreq frequency scaling driver?

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https://bugs.launchpad.net/bugs/1477171

Title:
  Enable intel_pstate by default on Trusty EC2 AMIs

Status in linux package in Ubuntu:
  In Progress

Bug description:
  Please can the intel_pstate driver be enabled by default on the Ubuntu
  EC2 AMIs. On instances with support for C-states and P-States [1]
  there is a notable performance impact and lack of support for higher
  clock frequencies available due to the use of the acpi-cpufreq driver.
  For example on a c4.8xlarge the default frequency is limited to 2.9GHz
  when 3.2GHz is supported by the chip [2]. Some additional analysis is
  available here [3] and re-enabling it by default has been discussed
  [4] but this request is specifically for the EC2 AMIs.

  [1] http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/processor_state_control.html
  [2] http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/c4-instances.html
  [3] http://www.deplication.net/2015/07/c-states-and-p-states-with-ubuntu-1404.html
  [4] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1188647

  AMI: ami-47a23a30 (eu-west-1)

  $ lsb_release -d
  Description:    Ubuntu 14.04.2 LTS

  $ uname -a
  Linux ip-172-31-8-218 3.13.0-57-generic #95-Ubuntu SMP Fri Jun 19 09:28:15 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

  Default configuration (c4.8xl):
  $ sudo cpupower frequency-info
  analyzing CPU 0:
    driver: acpi-cpufreq
    CPUs which run at the same hardware frequency: 0
    CPUs which need to have their frequency coordinated by software: 0
    maximum transition latency: 10.0 us.
    hardware limits: 1.20 GHz - 2.90 GHz
    available frequency steps: 2.90 GHz, 2.90 GHz, 2.80 GHz, 2.70 GHz, 2.50 GHz, 2.40 GHz, 2.30 GHz, 2.20 GHz, 2.00 GHz, 1.90 GHz, 1.80 GHz, 1.70 GHz, 1.60 GHz, 1.40 GHz, 1.30 GHz, 1.20 GHz
    available cpufreq governors: conservative, ondemand, userspace, powersave, performance
    current policy: frequency should be within 1.20 GHz and 2.90 GHz.
                    The governor "ondemand" may decide which speed to use
                    within this range.
    current CPU frequency is 1.20 GHz (asserted by call to hardware).
    cpufreq stats: 2.90 GHz:70.40%, 2.90 GHz:0.00%, 2.80 GHz:0.00%, 2.70 GHz:0.00%, 2.50 GHz:0.00%, 2.40 GHz:0.00%, 2.30 GHz:0.00%, 2.20 GHz:0.00%, 2.00 GHz:0.00%, 1.90 GHz:0.00%, 1.80 GHz:0.00%, 1.70 GHz:0.00%, 1.60 GHz:0.09%, 1.40 GHz:0.00%, 1.30 GHz:0.00%, 1.20 GHz:29.51%  (5)
    boost state support:
      Supported: yes
      Active: yes

  With intel_pstate enabled (c4.8xl):
  $ sudo cpupower frequency-info
  analyzing CPU 0:
    driver: intel_pstate
    CPUs which run at the same hardware frequency: 0
    CPUs which need to have their frequency coordinated by software: 0
    maximum transition latency: 0.97 ms.
    hardware limits: 1.20 GHz - 3.50 GHz
    available cpufreq governors: performance, powersave
    current policy: frequency should be within 1.20 GHz and 3.50 GHz.
                    The governor "performance" may decide which speed to use
                    within this range.
    current CPU frequency is 3.20 GHz (asserted by call to hardware).
    boost state support:
      Supported: yes
      Active: yes
  --- 
  AlsaDevices:
   total 0
   crw-rw---- 1 root audio 116,  1 Aug 12 17:19 seq
   crw-rw---- 1 root audio 116, 33 Aug 12 17:19 timer
  AplayDevices: Error: [Errno 2] No such file or directory
  ApportVersion: 2.14.1-0ubuntu3.11
  Architecture: amd64
  ArecordDevices: Error: [Errno 2] No such file or directory
  AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', '/dev/snd/timer'] failed with exit code 1:
  CRDA: Error: [Errno 2] No such file or directory
  CurrentDmesg: [39221.196411] init: plymouth-upstart-bridge main process ended, respawning
  DistroRelease: Ubuntu 14.04
  Ec2AMI: ami-47a23a30
  Ec2AMIManifest: (unknown)
  Ec2AvailabilityZone: eu-west-1b
  Ec2InstanceType: c4.8xlarge
  Ec2Kernel: unavailable
  Ec2Ramdisk: unavailable
  IwConfig: Error: [Errno 2] No such file or directory
  Lsusb: Error: command ['lsusb'] failed with exit code 1: unable to initialize libusb: -99
  MachineType: Xen HVM domU
  Package: linux (not installed)
  PciMultimedia:
   
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB:
   
  ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-61-generic root=UUID=877c5daf-9427-49e3-8656-437c3f30fc84 ro console=tty1 console=ttyS0
  ProcVersionSignature: User Name 3.13.0-61.100-generic 3.13.11-ckt22
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-61-generic N/A
   linux-backports-modules-3.13.0-61-generic  N/A
   linux-firmware                             N/A
  RfKill: Error: [Errno 2] No such file or directory
  Tags:  trusty ec2-images
  Uname: Linux 3.13.0-61-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm audio cdrom dialout dip floppy netdev plugdev sudo video
  _MarkForUpload: True
  dmi.bios.date: 05/06/2015
  dmi.bios.vendor: Xen
  dmi.bios.version: 4.2.amazon
  dmi.chassis.type: 1
  dmi.chassis.vendor: Xen
  dmi.modalias: dmi:bvnXen:bvr4.2.amazon:bd05/06/2015:svnXen:pnHVMdomU:pvr4.2.amazon:cvnXen:ct1:cvr:
  dmi.product.name: HVM domU
  dmi.product.version: 4.2.amazon
  dmi.sys.vendor: Xen

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