Providing accurate time-based counters for scaling operating frequencies of microprocessors

US7602874B2 · kind B2 · utility

Assignee

• International Business Machines Corporation · US

Inventors

• Rolf Hilgendorf · Eppelheim, DE
• Jens Kuenzer · Eppelheim, DE
• Cedric Lichtenau · Stuttgart, DE
• Thomas Pflueger · Echterdingen, DE
• Martin Recktenwald · Eppelheim, DE
• Andreas Schmid · Duisburg, DE

Key dates

• Filing date: Jan 26, 2006
• Grant date: Oct 13, 2009
• Expiry date: Sep 29, 2027

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03L7/06
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A mechanism provides accurate time-based counters for scaling operating frequencies of microprocessors. The mechanism makes use of a time-based counter circuit configuration in which a fixed frequency clock is derived from a PLL of the clock generation circuit of the microprocessor and is used to feed the external and internal timebase logic as well as a timebase accumulator counter. The timebase accumulator counter accumulates the tick events from the timebase logic between two core clocks. The accumulated value is transferred to the core clock domain on every clock edge of a scalable clock and the accumulator is then reset. Because the accumulated ticks are transferred to the core clock domain before the accumulator is reset, no ticks are ever lost using the circuitry of the illustrative embodiment.