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.
$ 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
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 docs.aws. amazon. com/AWSEC2/ latest/ UserGuide/ c4-instances. html www.deplication .net/2015/ 07/c-states- and-p-states- with-ubuntu- 1404.html /bugs.launchpad .net/ubuntu/ +source/ linux/+ bug/1188647
[2] http://
[3] http://
[4] https:/
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):
The governor "ondemand" may decide which speed to use
within this range.
$ 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.
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):
The governor "performance" may decide which speed to use
within this range.
$ 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.
current CPU frequency is 3.20 GHz (asserted by call to hardware).
boost state support:
Supported: yes
Active: yes