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1. US20070113015 - Power conservation via DRAM access reduction

Office
United States of America
Application Number 11351070
Application Date 09.02.2006
Publication Number 20070113015
Publication Date 17.05.2007
Grant Number 7516274
Grant Date 07.04.2009
Publication Kind B2
IPC
G06F 13/00
GPHYSICS
06COMPUTING; CALCULATING OR COUNTING
FELECTRIC DIGITAL DATA PROCESSING
13Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units
CPC
G06F 12/0802
GPHYSICS
06COMPUTING; CALCULATING; COUNTING
FELECTRIC DIGITAL DATA PROCESSING
12Accessing, addressing or allocating within memory systems or architectures
02Addressing or allocation; Relocation
08in hierarchically structured memory systems, e.g. virtual memory systems
0802Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
G06F 1/3203
GPHYSICS
06COMPUTING; CALCULATING; COUNTING
FELECTRIC DIGITAL DATA PROCESSING
1Details not covered by groups G06F3/00G06F13/00 and G06F21/00
26Power supply means, e.g. regulation thereof
32Means for saving power
3203Power management, i.e. event-based initiation of power-saving mode
G06F 1/3225
GPHYSICS
06COMPUTING; CALCULATING; COUNTING
FELECTRIC DIGITAL DATA PROCESSING
1Details not covered by groups G06F3/00G06F13/00 and G06F21/00
26Power supply means, e.g. regulation thereof
32Means for saving power
3203Power management, i.e. event-based initiation of power-saving mode
3206Monitoring of events, devices or parameters that trigger a change in power modality
3215Monitoring of peripheral devices
3225of memory devices
G06F 1/3275
GPHYSICS
06COMPUTING; CALCULATING; COUNTING
FELECTRIC DIGITAL DATA PROCESSING
1Details not covered by groups G06F3/00G06F13/00 and G06F21/00
26Power supply means, e.g. regulation thereof
32Means for saving power
3203Power management, i.e. event-based initiation of power-saving mode
3234Power saving characterised by the action undertaken
325Power saving in peripheral device
3275Power saving in memory, e.g. RAM, cache
G06F 12/0875
GPHYSICS
06COMPUTING; CALCULATING; COUNTING
FELECTRIC DIGITAL DATA PROCESSING
12Accessing, addressing or allocating within memory systems or architectures
02Addressing or allocation; Relocation
08in hierarchically structured memory systems, e.g. virtual memory systems
0802Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
0875with dedicated cache, e.g. instruction or stack
G06F 12/0888
GPHYSICS
06COMPUTING; CALCULATING; COUNTING
FELECTRIC DIGITAL DATA PROCESSING
12Accessing, addressing or allocating within memory systems or architectures
02Addressing or allocation; Relocation
08in hierarchically structured memory systems, e.g. virtual memory systems
0802Addressing of a memory level in which the access to the desired data or data block requires associative addressing means, e.g. caches
0888using selective caching, e.g. bypass
Applicants Sun Microsystems, Inc.
Inventors Moll Laurent R.
Song Seungyoon Peter
Glaskowsky Peter N.
Cheng Yu Qing
Agents Osha • Liang LLP
Title
(EN) Power conservation via DRAM access reduction
Abstract
(EN)

Power conservation via DRAM access reduction is provided by a buffer/mini-cache selectively operable in a normal mode and a buffer mode. In the buffer mode, entered when CPUs begin operating in low-power states, non-cacheable accesses (such as generated by a DMA device) matching specified physical address ranges are processed by the buffer/mini-cache, instead of by a memory controller and DRAM. The buffer/mini-cache processing includes allocating lines when references miss, and returning cached data from the buffer/mini-cache when references hit. Lines are replaced in the buffer/mini-cache according to one of a plurality of replacement policies, including ceasing replacement when there are no available free lines. In the normal mode, entered when CPUs begin operating in high-power states, the buffer/mini-cache operates akin to a conventional cache and non-cacheable accesses are not processed therein. In one usage scenario, data retained in the buffer/mini-cache is graphics refresh data maintained in a compressed format.