Method and apparatus for saving power for a computing system by providing instant-on resuming from a hibernation state

Abstract

The present invention "provides a computing system power-saving method and device for instantaneous power-on recovery from a dormant state". A computing system can save more power than S3 state by entering S4 state after long periods of inactivity, and has instant-on capability when resuming from S4 state by using a fast accessible non-volatile cache. When the system enters the S4 state, the memory contents are not stored to the disk drive, but are cached in the non-volatile cache. The non-volatile cache can be coupled to a bus that connects the disk drives with the disk controller. When resuming from the S4 state, memory contents can be read from the non-volatile cache instead of the slow disk drive. Both caching and restoration procedures can be performed in an OS-transparent manner. Mapping tables can be created and stored in the non-volatile cache during caching to provide efficient reads from the non-volatile cache during recovery.

Description

[0001] related application [0002] This application is related to commonly assigned U.S. Patent Application Ser.No.xx / xxx,xxx (Attorney's Record No. 42P24468), which is jointly applied by Ram Chary and Pradeep Sebastian and the title of the invention is "Configuring a Device for Operation on a Computing Platform (A device configured to operate on a computing platform)", also referring to commonly assigned U.S. Patent Application Ser. No. xx / xxx, xxx (Attorney's Record No. 42P24527), by R. , the title of the invention jointly applied by Shubha Kumbadakone and Shreekant S.Thakkar is "Method and Apparatus for Caching Memory Content on a Computing System to Facilitate Instant-On Resuming from a HibernationState." Method and apparatus for facilitating instant-on recovery from dormant state)". technical field [0003] The present invention generally relates to reduction of power consumption of computer systems, and in particular, but not exclusively, to methods and apparatus for p...

AI Technical Summary

Problems solved by technology

However, while the S4 state is perfect for power saving, it is in a long-latency sleep state due to the system context being saved to (and readback from) the hard disk drive (HDD)

Assuming microdrives are typically required for handheld PCs (to achieve form factor and cost targets), this results in recovery times that vary widely from 3-4 seconds (S3 recovery) to 30+ seconds (S4 recovery using microdrives)

In other words, although the S4 state saves more power than the S3 state, it slows down the PC's response time during wakeup, which is unacceptable in today's fast computing environment

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