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h4. CPU Power Management for x86 Systems
CPU power management for single and multiprocessor systems is available in the Solaris 10 OS (from the 5/08 update) and in OpenSolaris.
This feature monitors CPU utilization and lowers the CPU frequency (hence reducing power consumption) when utilization is low.
h4. Processor Support
Intel processors that belong to Family 0xF (Models >=0x3) or Family 0x6 (Models >=E), including:
* Pentium 4 and Intel Xeon processors
* Intel Core Solo and Intel Core Duo processors
* Intel Xeon Processor 5100 Series and Intel Core 2 Duo processors
[How to identify Intel CPU families|http://processorfinder.intel.com/default.aspx]
* AMD processors with Family >= 0x10 which includes Barcelona and Phenom products.
[How to identify AMD CPU families|http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25481.pdf]
Refer to your system documentation to ensure Power Management is enabled in the BIOS.
h4. How to Enable CPU Power Management
Feature is not enabled by default. Sysadmin must enable by editing /etc/power.conf
This file is used by the Power Management configuration program pmconfig(1M) to initialize the settings for Power Management. If you make changes to this file, you must run pmconfig(1M) manually for the changes to take effect.
To turn on CPU power management:
{noformat}
cpupm enable
{noformat}
To set CPU idle threshold, in this case to 15 seconds:
{noformat}
cpu-threshold 15s
{noformat}
To inspect the current CPU clock frequency to ensure CPU frequency reduction has taken effect:
{noformat}
$ kstat -m cpu_info -s current_clock_Hz
{noformat}
h5. Additional Resources
* Sun BluePrints documents:
** [Sun's Approach To Intelligent Power Monitoring|http://wikis.sun.com/display/BluePrints/Sun%27s+Approach+To+Intelligent+Power+Monitoring]
** [Energy Efficient Datacenters: Electrical Design|http://wikis.sun.com/display/BluePrints/Energy+Efficient+Datacenters+-+Electrical+Design]
* Solaris uses the Monitor/Mwait instructions to avoid executing CPU cycles (and wasting power) in idle loops. See [http://bugs.opensolaris.org/view_bug.do?bug_id=6495392|http://bugs.opensolaris.org/view_bug.do?bug_id=6495392] and [http://blogs.sun.com/bholler/entry/the_most_executed_code_in|http://blogs.sun.com/bholler/entry/the_most_executed_code_in]
* [OpenSolaris Power Management Community|http://www.opensolaris.org/os/community/pm/]
* [Opensolaris Enhanced Power Management: Project Tesla|https://opensolaris.org/os/project/tesla/]
* [Powertop|http://softwareblogs.intel.com/2008/05/19/powertop-10-on-solaris/] \- a tool to investigate power usage on a running system
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h4. CPU Power Management for x86 Systems
CPU power management for single and multiprocessor systems is available in the Solaris 10 OS (from the 5/08 update) and in OpenSolaris.
This feature monitors CPU utilization and lowers the CPU frequency (hence reducing power consumption) when utilization is low.
h4. Processor Support
Intel processors that belong to Family 0xF (Models >=0x3) or Family 0x6 (Models >=E), including:
* Pentium 4 and Intel Xeon processors
* Intel Core Solo and Intel Core Duo processors
* Intel Xeon Processor 5100 Series and Intel Core 2 Duo processors
[How to identify Intel CPU families|http://processorfinder.intel.com/default.aspx]
* AMD processors with Family >= 0x10 which includes Barcelona and Phenom products.
[How to identify AMD CPU families|http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/25481.pdf]
Refer to your system documentation to ensure Power Management is enabled in the BIOS.
h4. How to Enable CPU Power Management
Feature is not enabled by default. Sysadmin must enable by editing /etc/power.conf
This file is used by the Power Management configuration program pmconfig(1M) to initialize the settings for Power Management. If you make changes to this file, you must run pmconfig(1M) manually for the changes to take effect.
To turn on CPU power management:
{noformat}
cpupm enable
{noformat}
To set CPU idle threshold, in this case to 15 seconds:
{noformat}
cpu-threshold 15s
{noformat}
To inspect the current CPU clock frequency to ensure CPU frequency reduction has taken effect:
{noformat}
$ kstat -m cpu_info -s current_clock_Hz
{noformat}
h5. Additional Resources
* Sun BluePrints documents:
** [Sun's Approach To Intelligent Power Monitoring|http://wikis.sun.com/display/BluePrints/Sun%27s+Approach+To+Intelligent+Power+Monitoring]
** [Energy Efficient Datacenters: Electrical Design|http://wikis.sun.com/display/BluePrints/Energy+Efficient+Datacenters+-+Electrical+Design]
* Solaris uses the Monitor/Mwait instructions to avoid executing CPU cycles (and wasting power) in idle loops. See [http://bugs.opensolaris.org/view_bug.do?bug_id=6495392|http://bugs.opensolaris.org/view_bug.do?bug_id=6495392] and [http://blogs.sun.com/bholler/entry/the_most_executed_code_in|http://blogs.sun.com/bholler/entry/the_most_executed_code_in]
* [OpenSolaris Power Management Community|http://www.opensolaris.org/os/community/pm/]
* [Opensolaris Enhanced Power Management: Project Tesla|https://opensolaris.org/os/project/tesla/]
* [Powertop|http://softwareblogs.intel.com/2008/05/19/powertop-10-on-solaris/] \- a tool to investigate power usage on a running system
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