OCCAM: An Error Oblivious CAM

Yuval Harary; Paz Snapir; Eyal Reshef; Esteban Garzon; Leonid Yavits

doi:10.1109/LSSC.2024.3362891

OCCAM: An Error Oblivious CAM

Yuval Harary
, Paz Snapir
, Eyal Reshef
, Esteban Garzon
, Leonid Yavits

Bar-Ilan University - The Alexander Kofkin Faculty of Engineering

Research output: Contribution to journal › Article › peer-review

10 Scopus citations

Abstract

Content addressable memories (CAMs) are widely used in many applications in general purpose computer microarchitecture, networking and domain-specific hardware accelerators. In addition to storing and reading data, CAMs enable simultaneous compare of query datawords with the entire memory content. Similar to SRAM and DRAM, CAMs are prone to errors and faults. While error correcting codes (ECCs) are widely used in DRAM and SRAM, they are not directly applicable in CAM: if a dataword that is supposed to match a query altered due to an error, it will falsely mismatch even if it is ECC-encoded. We propose OCCAM, an error oblivious CAM, which combines ECC and approximate search (matching) to allow tolerating a large and dynamically configurable number of errors. We manufactured the OCCAM silicon prototype using 65-nm commercial process and verified its error tolerance capabilities through silicon measurements. OCCAM tolerates 11% error rate (7 bit errors in each 64-bit memory row) with 100% sensitivity and specificity.

Original language	English
Pages (from-to)	82-85
Number of pages	4
Journal	IEEE Solid-State Circuits Letters
Volume	7
DOIs	https://doi.org/10.1109/LSSC.2024.3362891
State	Published - 2024

Bibliographical note

Publisher Copyright:
© 2018 IEEE.

Funding

This work was supported in part by the European Union s Horizon Europe Program for Research and Innovation under Grant 101047160; in part by the Israeli Ministry of Science and Technology through Lise Meitner Grant for Israeli-Swedish Research Collaboration under Grant 1001569396; and in part by the Israeli Ministry of Science and Technology Grant for Groundbreaking Research under Grant 1001702600. The work of Esteban Garzón was supported by the Italian Ministry for Universities and Research (MUR) through the Call "Horizon Europe 2021 2027 Program under Grant H25F21001420001."

Funders	Funder number
European Union s Horizon Europe Program for Research and Innovation	101047160
Horizon Europe 2021 2027 Program	H25F21001420001
Ministero dell’Istruzione, dell’Università e della Ricerca
Ministry of science and technology, Israel	1001569396, 1001702600

Keywords

Content addressable memory (CAM)
Hamming distance (HD)
error correcting codes (ECCs)
error tolerance

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10.1109/LSSC.2024.3362891

Cite this

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title = "OCCAM: An Error Oblivious CAM",

abstract = "Content addressable memories (CAMs) are widely used in many applications in general purpose computer microarchitecture, networking and domain-specific hardware accelerators. In addition to storing and reading data, CAMs enable simultaneous compare of query datawords with the entire memory content. Similar to SRAM and DRAM, CAMs are prone to errors and faults. While error correcting codes (ECCs) are widely used in DRAM and SRAM, they are not directly applicable in CAM: if a dataword that is supposed to match a query altered due to an error, it will falsely mismatch even if it is ECC-encoded. We propose OCCAM, an error oblivious CAM, which combines ECC and approximate search (matching) to allow tolerating a large and dynamically configurable number of errors. We manufactured the OCCAM silicon prototype using 65-nm commercial process and verified its error tolerance capabilities through silicon measurements. OCCAM tolerates 11\% error rate (7 bit errors in each 64-bit memory row) with 100\% sensitivity and specificity.",

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OCCAM: An Error Oblivious CAM

Abstract

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Keywords

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