Non-interference and local correctness in transactional memory

Kuznetsov, Petr; Peri, Sathya

doi:10.1016/j.tcs.2016.06.021

Cited by 11 publications

(17 citation statements)

References 14 publications

(30 reference statements)

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“…(2) transaction can not invoke any other method after receiving the response as C or A . Sequential Histories: Following [2,30], if all the methods of the history are complete and isolated from each other, i.e. all the methods of history are atomic and following the total order in H. So, with this assumption, the only relevant methods of a transaction T i are l i (k, v), l i (k, A ), i i (k, v), d i (k, v), STM tryC i (C ) (or c i for short), STM tryC i (A ), and STM tryA i (A ) (or a k for short).…”

Section: System Model and Preliminariesmentioning

confidence: 99%

“…Local Opacity (or LO): It is an another popular correctness criteria for STMs which is less restrictive than opacity. Local-opacity [2] is a superclass of opacity. It considers a set of sub-histories for history H, denoted as H.subhistSet as follows: (1) We construct a subhist corresponding to each aborted transaction T i while including all the events evts() of previously committed transactions along with all successful evts() of T i (i.e., evts() which has not returned A yet) and put committed C immediately after last successful operation of T i ; (2) We construct one more sub-history corresponding to last committed transaction T l which considers all the previously committed transactions only including T l .…”

Section: System Model and Preliminariesmentioning

confidence: 99%

“…If all the above defined sub-histories H.subhistSet for a history H are opaque then H is said to be locally-opaque [2]. We can observe that a sub-history corresponding to an aborted transaction T i contains evts() from only one aborted transaction which is T i itself and does not consider any other live/aborted transactions.…”

Section: System Model and Preliminariesmentioning

confidence: 99%

“…STMs ensure that consistency issues such as deadlock, livelock, priority inversion, etc will not occur. It provides a high-level abstraction to the programmer with the popular correctness criteria opacity [1], local opacity [2] which consider all the transactions (a piece of code) including aborted one as well in † Author sequence follows the lexical order of last names. All the authors can be contacted at the addresses given above.…”

Section: Introductionmentioning

confidence: 99%

“…-Initially, we propose Starvation-Freedom for Single-Version OSTM as SF-SVOSTM which satisfies correctness criteria as conflict-opacity (or co-opacity) [6]. -To achieve the greater concurrency further, we propose Starvation-Freedom for Multi-Version OSTM as SF-MVOSTM in Section 3 which maintains multiple versions corresponding to each key and satisfies the correctness as local opacity [2]. -We propose SF-SVOSTM and SF-MVOSTM for hash table and linked-list data structure describe in SubSection3.2 but its generic for other data structures as well.…”

Section: Introductionmentioning

confidence: 99%

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Achieving Starvation-Freedom with Greater Concurrency in Multi-Version Object-based Transactional Memory Systems

Juyal

Kulkarni

Kumari

et al. 2019

Lecture Notes in Computer Science

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To utilize the multi-core processors properly concurrent programming is needed. The main challenge is to design a correct and efficient concurrent program. Software Transactional Memory Systems (STMs) provide ease of multithreading to the programmer without worrying about concurrency issues as deadlock, livelock, priority inversion, etc. Most of the STMs work on read-write operations known as RWSTMs. Some STMs work at higher-level operations and ensure greater concurrency than RWSTMs. Such STMs are known as Single-Version Object-based STMs (SVOSTMs). The transactions of SVOSTMs can return commit or abort. Aborted SVOSTMs transactions retry. But in the current setting of SVOSTMs, transactions may starve. So, we propose a Starvation-Freedom in SVOSTM as SF-SVOSTM that satisfies the correctness criteria conflict-opacity. Databases and STMs say that maintaining multiple versions corresponding to each shared data-item (or key) reduces the number of aborts and improves the throughput. So, to achieve greater concurrency further, we propose Starvation-Freedom in Multi-Version OSTM as SF-MVOSTM algorithm. The number of versions maintains by SF-MVOSTM either be unbounded with garbage collection as SF-MVOSTM-GC or bounded with latest K-versions as SF-KOSTM. SF-MVOSTM satisfies the correctness criteria as local opacity and shows the performance benefits as compared with state-of-the-art STMs.

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Section: System Model and Preliminariesmentioning

confidence: 99%

Section: System Model and Preliminariesmentioning

confidence: 99%

Section: System Model and Preliminariesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Achieving Starvation-Freedom with Greater Concurrency in Multi-Version Object-based Transactional Memory Systems

Juyal

Kulkarni

Kumari

et al. 2019

Lecture Notes in Computer Science

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An Innovative Approach to Achieve Compositionality Efficiently Using Multi-version Object Based Transactional Systems

Juyal

Kulkarni

Kumari

et al. 2018

Lecture Notes in Computer Science

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In the modern era of multi-core systems, the main aim is to utilize the cores properly.This utilization can be done by concurrent programming. But developing a flawless and well-organized concurrent program is difficult. Software Transactional Memory Systems (STMs) are a convenient programming interface which assist the programmer to access the shared memory concurrently without worrying about consistency issues such as priority-inversion, deadlock, livelock, etc. Another important feature that STMs facilitate is compositionality of concurrent programs with great ease. It composes different concurrent operations in a single atomic unit by encapsulating them in a transaction.Many STMs available in the literature execute read/write primitive operations on memory buffers. We represent them as Read-Write STMs or RWSTMs. Whereas, there exist some STMs (transactional boosting and its variants) which work on higher level operations such as insert, delete, lookup, etc. on a hash-table. We refer these STMs as Object Based STMs or OSTMs. The literature of databases and RWSTMs say that maintaining multiple versions 1 A preliminary version of this paper appeared in 20th International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS 2018) and awarded with the Best Student Paper Award. A poster version of this work received Best Poster Award in NETYS 2018. 2 Author sequence follows the lexical order of last names. All the authors can be contacted at the addresses given above. Archit Somani's phone number: +91 -7095044601. ensures greater concurrency. This motivates us to maintain multiple version at higher level with object semantics and achieves greater concurrency. So, this paper proposes the notion of Optimized Multi-version Object Based STMs or OPT-MVOSTMs which encapsulates the idea of multiple versions in OSTMs to harness the greater concurrency efficiently. For efficient memory utilization, we develop two variations of OPT-MVOSTMs. First, OPT-MVOSTM with garbage collection (or OPT-MVOSTM-GC) which uses unbounded versions but performs garbage collection scheme to delete the unwanted versions. Second, finite version OPT-MVOSTM (or OPT-KOSTM) which maintains at most K versions by replacing the oldest version when (K + 1) th version is created by the current transaction. We propose the OPT-MVOSTMs for hash-table and list objects as OPT-HT-MVOSTM and OPT-list-MVOSTM respectively. For memory utilization, we propose two variants of both the algorithms as OPT-HT-MVOSTM-GC, OPT-HT-KOSTM and OPT-list-MVOSTM-GC, OPT-list-KOSTM respectively. OPT-HT-KOSTM performs best among its variants and outperforms state-of-the-art hash-table based STMs (HT-OSTM, ESTM, RWSTM, HT-MVTO, HT-KSTM) by a factor of 3.62, 3.95, 3.44, 2.75, 1.85 for workload W1 (90% lookup, 8% insert and 2% delete), 1. 44, 2.36, 4.45, 9.84, 7.42 for workload W2 (50% lookup, 25% insert and 25% delete), and 2. 11, 4.05, 7.84, 12.94, 10.70 for workload W3 (10% lookup, 45% insert and 45% delete) respectively. Similarly, OPT-list-KOSTM performs ...

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Efficient Means of Achieving Composability Using Object Based Semantics in Transactional Memory Systems

2019

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Composing together the individual atomic methods of concurrent data-structures (cds) pose multiple design and consistency challenges. In this context composition provided by transactions in software transaction memory (STM) can be handy. However, most of the STMs offer read/write primitives to access shared cds. These read/write primitives result in unnecessary aborts. Instead, semantically rich higher-level methods of the underlying cds like lookup, insert or delete (in case of hash-table or lists) aid in ignoring unimportant lower level read/write conflicts and allow better concurrency.In this paper, we adapt transaction tree model in databases to propose OSTM which enables efficient composition in cds. We extend the traditional notion of conflicts and legality to higher level methods of cds using STMs and lay down detailed correctness proof to show that it is co-opaque. We implement OSTM with concurrent closed addressed hash-table (HT-OSTM) and list (list-OSTM) which exports the higher-level operations as transaction interface.In our experiments with varying workloads and randomly generated transaction operations, HT-OSTM shows speedup of 3 to 6 times and w.r.t aborts HT-OSTM is 3 to 7 times better than ESTM and read/write based STM, respectively. Where as, list-OSTM outperforms state of the art lock-free transactional list, NOrec STM list and boosted list by 30% to 80% across all workloads and scenarios. Further, list-OSTM incurred negligible aborts in comparison to other techniques considered in the paper. * A preliminary version of this work was accepted in AADDA 2018 as work in progress. † Author sequence follows lexical order of last names.

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Non-interference and local correctness in transactional memory

Cited by 11 publications

References 14 publications

Achieving Starvation-Freedom with Greater Concurrency in Multi-Version Object-based Transactional Memory Systems

Achieving Starvation-Freedom with Greater Concurrency in Multi-Version Object-based Transactional Memory Systems

An Innovative Approach to Achieve Compositionality Efficiently Using Multi-version Object Based Transactional Systems

Efficient Means of Achieving Composability Using Object Based Semantics in Transactional Memory Systems

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