SPECULA: Speculative Replication of Software Transactional Memory

Abstract

Abstract-This paper introduces SPECULA, a novel replication protocol for Software Transactional Memory (STM) systems that seeks maximum overlap between transaction execution and replica synchronization phases via speculative processing techniques. By removing the replica synchronization phase from the critical path of execution of transactions, SPEC-ULA allows threads to speculatively pipeline the execution of both transactional and/or non-transactional code. The core of SPECULA is a multi-version concurrency control algorithm that supports speculative transaction processing while ensuring the strong consistency criteria that are desirable in non-sandboxed environments like STMs. Via an experimental study, based on a fully-fledged prototype and on both synthetic and standard STM benchmarks, we demonstrate that SPECULA can achieve speedups of up to one order of magnitude with respect to state-of-the-art non-speculative replication techniques.

Dealing with Interactive Transactions in a Byzantine Fault Tolerant STM

“…Em transações pré-declaradas, o cliente necessita enviar todo código transacional para as réplicas 5 . Nas transações interativas, o cliente interage com as réplicas, enviando operação por operação.…”

“…Pesquisadores têm mostrado um aumento de interesse no controle de concorrência utilizando STM, como pode ser visto no trabalhos D 2 ST M [3], RAM-DUR [4], SPEC-ULA [5], OSARE [6], SCert [7], AGGRO [8], STR [9], Granola [10] e Zhang [11]. Ao utilizar STM, os programadores não precisam lidar com mecanismos explícitos de controle de concorrência (como monitores, locks ou semáforos).…”

Speculative client execution in deferred update replication

“…Speculation is a widely used technique for anticipating work based on uncertain inputs [3,14,16,16,1]. Some of these works process transactions speculatively along di↵er-ent serialization orders [14,3], whereas others [16,1] fix a single order at the beginning and follow it.…”

“…Some of these works process transactions speculatively along di↵er-ent serialization orders [14,3], whereas others [16,1] fix a single order at the beginning and follow it. This intuition is the same as X-DUR but the deployment is di↵erent.…”

“…This intuition is the same as X-DUR but the deployment is di↵erent. X-DUR speculates on the processing of client transactions before invoking the global certification layer (or the ordering layer as in [16,14]). Finally [1] applies speculation to parallelize di↵erent parts of a transactions.…”