Dynamic P-States Feature

This new feature adds the ability to control processor performance from within HP-UX, allowing systems to conserve power when not fully loaded. Requires Intel® Itanium® 9100 series or later processors.

Summary of Change

A new command, pstatectl(1M), is provided to control the new functionality. A startup script and associated configuration file (/etc/rc.config.d/pstate) are also included. To obtain the manpage for the pstatectl command, download PHCO_39261 from the ITRC website: http://itrc.hp.com.

Impact

Unless you explicitly turn on this new feature, there will be no impact. When this feature is enabled, some workloads may show some minor performance impact in terms of throughput or responsiveness. At the same time, you can expect to see up to an 8% reduction in CPU power on systems with Intel® Itanium® 9100 series processors.

Compatibility

The Dynamic P-States feature requires Intel® Itanium® 9100 series or later processors. There is no equivalent feature available for PA-RISC processors.

Systems with Intel® Itanium® 9100 series processors must have the following firmware or a later version:

BL860c, BL870c: SFW 04.05 or later
rx2660, rx3600, rx6600: SFW 04.03 or later
rx7640, rx8640: SFW 4.1 or later
HP Integrity Superdome, sx2000: SFW 8.7e or later

Performance

When used to reduce system power consumption, there will be a reduction in performance according to the power mode selected. In the suggested dynamic power savings mode, the performance loss will generally be less than 1%.

Documentation

To obtain the manpage for the pstatectl command, download PHCO_39261 from the ITRC website: http://itrc.hp.com.

Obsolescence

Not applicable.