Nonblocking Memory Refresh

Since its inception half a century ago, DRAM has required dynamic/active refresh operations that block read requests and decrease performance. We propose refreshing DRAM in the background without stalling read accesses to refreshing memory blocks, similar to the static/background refresh in SRAM. Our proposed Nonblocking Refresh works by refreshing a portion of the data in a memory block at a time and uses redundant data, such as Reed-Solomon codes, in the block to compute the block's refreshing/unreadable data to satisfy read requests. For proof of concept, we apply Nonblocking Refresh to server memory systems, where every memory block already contains redundant data to provide hardware failure protection. In this context, Nonblocking Refresh can utilize server memory system's existing per-block redundant data in the common-case when there are no hardware faults to correct, without requiring any dedicated redundant data of its own. Our evaluations show that on average across five server memory systems with different redundancy and failure protection strengths, Nonblocking Refresh improves performance by 16.2% and 30.3% for 16gb and 32gb DRAM chips, respectively.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Computer Science and Applications

Department dc:contributor.department

Computer Science

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2018

Author dc:creator

• Nguyen, Kate Vy Hoang

Chair dc:contributor.committeechair

• Jian, Xun

Committee members dc:contributor.committeemember

• Back, Godmar V.
• Butt, Ali R.

• Memory Systems
• Dependable Architectures

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

vt_gsexam:16643

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/84523