DocumentCode :
2582575
Title :
Reducing memory reference energy with opportunistic virtual caching
Author :
Basu, Arkaprava ; Hill, Mark D. ; Swift, Michael M.
Author_Institution :
Univ. of Wisconsin-Madison, Madison, WI, USA
fYear :
2012
fDate :
9-13 June 2012
Firstpage :
297
Lastpage :
308
Abstract :
Most modern cores perform a highly-associative transaction look aside buffer (TLB) lookup on every memory access. These designs often hide the TLB lookup latency by overlapping it with L1 cache access, but this overlap does not hide the power dissi-pated by TLB lookups. It can even exacerbate the power dissipation by requiring higher associativity L1 cache. With today´s concern for power dissipation, designs could instead adopt a virtual L1 cache, wherein TLB access power is dissipated only after L1 cache misses. Unfortunately, virtual caches have compatibility issues, such as supporting writeable synonyms and x86´s physical page table walker. This work proposes an Opportunistic Virtual Cache (OVC) that exposes virtual caching as a dynamic optimization by allowing some memory blocks to be cached with virtual addresses and others with physical addresses. OVC relies on small OS changes to signal which pages can use virtual caching (e.g., no writeable synonyms), but defaults to physical caching for compatibility. We show OVC´s promise with analysis that finds virtual cache problems exist, but are dynamically rare. We change 240 lines in Linux 2.6.28 to enable OVC. On experiments with Parsec and commercial workloads, the resulting system saves 94-99% of TLB lookup energy and nearly 23% of L1 cache dynamic lookup energy.
Keywords :
cache storage; dynamic programming; power aware computing; OVC; TLB; dynamic optimization; memory access; memory blocks; memory reference energy; opportunistic virtual cache; opportunistic virtual caching; physical page table walker; power dissipation; transaction look aside buffer; virtual addresses; writeable synonyms; Coherence; Energy consumption; Hardware; Indexing; Kernel; Linux; Optimization;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Computer Architecture (ISCA), 2012 39th Annual International Symposium on
Conference_Location :
Portland, OR
ISSN :
1063-6897
Print_ISBN :
978-1-4673-0475-7
Electronic_ISBN :
1063-6897
Type :
conf
DOI :
10.1109/ISCA.2012.6237026
Filename :
6237026
Link To Document :
بازگشت