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Record W3174520665 · doi:10.1145/3409964.3461820

PHPRX: An Efficient Hash Table for Persistent Memory

2021· article· en· W3174520665 on OpenAlexaff
Diego Cepeda, Wojciech Golab

Bibliographic record

Venuenot available
Typearticle
Languageen
FieldComputer Science
TopicParallel Computing and Optimization Techniques
Canadian institutionsUniversity of Waterloo
Fundersnot available
KeywordsComputer scienceParallel computingOperating systemMemory managementAllocatorCAS latencyInterleaved memoryMemory mapHash tableHash functionSemiconductor memoryEmbedded systemMemory controllerProgramming language

Abstract

fetched live from OpenAlex

Volatile media have dominated the realm of main memory on servers and desktop computers for decades. In 2019, Intel released the Optane Data Center Persistent Memory Module (DCPMM), which offers the capacity and persistence of block devices while providing the byte addressability and low latency of DRAM. These new memory modules allow programmers to develop data structures that can survive in main memory across crashes and power failures, without relying on secondary power sources such as batteries. This work presents the design of a persistent memory hash table data structure that incorporates several features to maximize efficiency: the locks for concurrency control are kept in volatile DRAM, an embedded memory allocator is used, a parallel table resize operation is implemented, and a mechanism is provided to incrementally expand the underlying memory-mapped file. We compare PHPRX experimentally against the Dash persistent memory hash table published recently by Lu et al., and demonstrate substantial speed-ups on an Intel Xeon server equipped with genuine Intel Optane DCPMM. Our performance advantage holds despite PHPRX using a space-efficient incremental approach to expanding the underlying memory-mapped file, as opposed to the much simpler static allocation approach used by Dash.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.001
metaresearch head score (Gemma)0.003
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.007
Threshold uncertainty score0.024

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0010.003
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0010.001
Scholarly communication0.0020.003
Open science0.0030.002
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0070.002

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.026
GPT teacher head0.267
Teacher spread0.240 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designSimulation or modeling
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations1
Published2021
Admission routes1
Has abstractyes

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