LongRun & power management (Score 4)

It is incorrect that LongRun only works with APM.

In fact, LongRun samples all traditional power management activity, which is:

• AutoHALT (ACPI: "C1")
  • x86 HLT instruction;
• Quick Start (ACPI: "C2")
  • Internal CPU clocks off (responding to a STPCLK# signal from the south bridge);
  • CPU is responsible for maintaining cache coherency;
• Deep Sleep (ACPI: "C3")
  • External bus clock removed from the CPU (by the south bridge);
  • System is resonsible for maintaining cache coherency.

LongRun effectively samples the time spent in these power management states, and converts it into a fraction of the overall sampling interval. This fraction directly determines the target CPU performance percentage.

APM is the older, BIOS-based implementation to exercise the above CPU power management states. ACPI is the new OS-based implementation to exercise the CPU power management states.

Neither APM nor ACPI are necessary for LongRun to function efficiently. In fact, LongRun works perfectly well with all OS's that are smart enough to invoke HLT whenever their scheduler (or GUI event loop) idles. This is true at least for all modern operating systems (all recent Windows versions, Linux and OS/2).

As a result, LongRun transparently works without any BIOS or OS modifications on pretty much all OS's you care about.

Cheers,

Marc