A fault-tolerant last level cache for CMPs operating at ultra-low voltage

Voltage scaling to values near the threshold voltage is a promising technique to hold off the many-core power wall. However, as voltage decreases, some SRAM cells are unable to operate reliably and show a behavior consistent with a hard fault. Block disabling is a micro-architectural technique that...

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Bibliographic Details
Published in:Journal of parallel and distributed computing Vol. 125; pp. 31 - 44
Main Authors: Ferrerón, Alexandra, Alastruey-Benedé, Jesús, Suárez Gracia, Darío, Monreal Arnal, Teresa, Ibáñez Marín, Pablo, Viñals Yúfera, Víctor
Format: Journal Article Publication
Language:English
Published: Elsevier Inc 01.03.2019
Elsevier
Subjects:
Arquitectura de computadors
Cache management
Fault-tolerance
Fault-tolerant computing
Informàtica
Multiprogramació (Ordinadors electrònics)
Multiprogramming (Electronic computers)
Near-threshold voltage
On-chip caches
SRAM reliability
Tolerància als errors (Informàtica)
Àrees temàtiques de la UPC
SRAM reliability
Near-threshold voltage
Cache management
Fault-tolerance
On-chip caches
ISSN:0743-7315, 1096-0848
Online Access:Get full text
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Summary:Voltage scaling to values near the threshold voltage is a promising technique to hold off the many-core power wall. However, as voltage decreases, some SRAM cells are unable to operate reliably and show a behavior consistent with a hard fault. Block disabling is a micro-architectural technique that allows low-voltage operation by deactivating faulty cache entries, at the expense of reducing the effective cache capacity. In the case of the last-level cache, this capacity reduction leads to an increase in off-chip memory accesses, diminishing the overall energy benefit of reducing the voltage supply. In this work, we exploit the reuse locality and the intrinsic redundancy of multi-level inclusive hierarchies to enhance the performance of block disabling with negligible cost. The proposed fault-aware last-level cache management policy maps critical blocks, those not present in private caches and with a higher probability of being reused, to active cache entries. Our evaluation shows that this fault-aware management results in up to 37.3% and 54.2% fewer misses per kilo instruction (MPKI) than block disabling for multiprogrammed and parallel workloads, respectively. This translates to performance enhancements of up to 13% and 34.6% for multiprogrammed and parallel workloads, respectively. •Fault-Tolerant Last Level Cache for CMPs Operating at Ultra-Low Voltage.•Mechanism that exploits redundancy and reuse to enhance block disabling performance.•Fault-aware LLC management that maps critical blocks to operative cache entries.•Detailed evaluation of block disabling techniques in a shared-memory coherent CMP.
ISSN:0743-7315
1096-0848
DOI:10.1016/j.jpdc.2018.10.010