Process Performance State Manager (PPSM)

Process Performance State Manager (PPSM) is a static library that implements the Enhanced Intel SpeedStep Technology (EIST), and System State S3 (Suspend to RAM) and S5 (Suspend to Disk) power management support.

PPSM supports the following power management modes:

• C0 processor state — Full ON
• C1 processor state — Auto-Halt
• Enhanced Intel SpeedStep (dynamic on demand CPU clock switching).
• S3 system state — Suspend to RAM
• S5 system state — Suspend to Disk

By default, the system remains in the C0 state at the maximum clock rate. Whenever the CPU idle thread is running, the C1 state is entered.

You can:

• enable or disable EIST at any time
• set upper and lower threshold values for CPU loading. The SpeedStep algorithm strives to hold the CPU loading between these two limits (relative to the current SpeedStep operating point). These threshold values are specified as percentages of CPU loading.
• set the integration interval (in milliseconds) used to determine the current CPU load
• request that the system be immediately boosted to the highest (fastest) operating point
• query the system to determine the current SpeedStep operating point and the current CPU load for each CPU (threads) in the system

For more information about the Enhanced Intel SpeedStep Technology, see http://www.intel.com/support/processors/sb/CS-028855.htm.