scholarly journals STM: Lock-Free Synchronization

2014 ◽  
pp. 206-212
Author(s):  
Ryan Saptarshi Ray
Keyword(s):  
Parallel Programming ◽  
Shared Memory ◽  
Concurrency Control ◽  
Control Mechanism ◽  
Parallel Processors ◽  
Software Transactional Memory ◽  
New Approach ◽  
Low Level ◽  
Complex Interactions ◽  
Design Program

Current parallel programming uses low-level programming constructs like threads and explicit synchronization (for example, locks, semaphores and monitors) to coordinate thread execution which makes these programs difficult to design, program and debug. In this paper we present Software Transactional Memory (STM) which is a promising new approach for programming in parallel processors having shared memory. It is a concurrency control mechanism that is widely considered to be easier to use by programmers than other mechanisms such as locking. It allows portions of a program to execute in isolation, without regard to other, concurrently executing tasks. A programmer can reason about the correctness of code within a transaction and need not worry about complex interactions with other, concurrently executing parts of the program.

scholarly journals LOCK-FREE DINING PHILOSOPHER

2017 ◽  
pp. 121-125
Author(s):  
VENKATAKASH RAJ RAOJILLELAMUDI ◽  
SOURAV MUKHERJEE ◽  
Ryan Saptarshi Ray ◽  
Utpal Kumar Ray
Keyword(s):  
Concurrency Control ◽  
Transactional Memory ◽  
Performance Comparison ◽  
Parallel Programs ◽  
Software Transactional Memory ◽  
Slowing Down ◽  
Complex Interactions ◽  
Design Program ◽  
Suboptimal Solution ◽  
Processor Speed

The past few years have marked the start of a historic transition from sequential to parallel computation.The necessity to write parallel programs is increasing as systems are getting more complex while processor speed increases are slowing down. Current parallel programming uses low-level programming constructs like threads and explicit synchronization using locks to coordinate thread execution. Parallel programs written with these constructs are difficult to design, program and debug. Also locks have many drawbacks which make them a suboptimal solution. Software Transactional Memory (STM) is a promising new approach to programming shared-memory parallel processors. It is a concurrency control mechanism that is widely considered to be easier to use by programmers than locking. It allows portions of a program to execute in isolation, without regard to other, concurrently executing tasks. A programmer can reason about the correctness of code within a transaction and need not worry about complex interactions with other, concurrently executing parts of the program. This paper shows the concept of writing code using Software Transactional Memory (STM) and the performance comparison of codes using locks with those using STM.

scholarly journals Cigarette-Smokers’ Problem with STM

2017 ◽  
pp. 130-135
Author(s):  
Rup Kamal ◽  
Ryan Saptarshi Ray ◽  
Utpal Kumar Ray ◽  
Parama Bhaumik
Keyword(s):  
Parallel Processing ◽  
Concurrency Control ◽  
Transactional Memory ◽  
Performance Comparison ◽  
Critical Section ◽  
Parallel Programs ◽  
Software Transactional Memory ◽  
Complex Interactions ◽  
Processor Speed ◽  
Better Than

The past few years have marked the start of a historic transition from sequential to parallel computation. The necessity to write parallel programs is increasing as systems are getting more complex while processor speed increases are slowing down. Current parallel programming uses low-level programming constructs like threads and explicit synchronization using locks to coordinate thread execution. Parallel programs written with these constructs are difficult to design, program and debug. Also locks have many drawbacks which make them a suboptimal solution. One such drawback is that locks should be only used to enclose the critical section of the parallel-processing code. If locks are used to enclose the entire code then the performance of the code drastically decreases. Software Transactional Memory (STM) is a promising new approach to programming shared-memory parallel processors. It is a concurrency control mechanism that is widely considered to be easier to use by programmers than locking. It allows portions of a program to execute in isolation, without regard to other, concurrently executing tasks. A programmer can reason about the correctness of code within a transaction and need not worry about complex interactions with other, concurrently executing parts of the program. If STM is used to enclose the entire code then the performance of the code is the same as that of the code in which STM is used to enclose the critical section only and is far better than code in which locks have been used to enclose the entire code. So STM is easier to use than locks as critical section does not need to be identified in case of STM. This paper shows the concept of writing code using Software Transactional Memory (STM) and the performance comparison of codes using locks with those using STM. It also shows why the use of STM in parallel-processing code is better than the use of locks.

scholarly journals Proving Opacity of Transactional Memory with Early Release

2015 ◽  
Vol 40 (4) ◽  
pp. 317-335
Author(s):  
Konrad Siek ◽  
Paweł T. Wojciechowski
Keyword(s):  
Shared Memory ◽  
Gold Standard ◽  
Concurrency Control ◽  
Transactional Memory ◽  
The Other ◽  
Proof Technique ◽  
Safety Properties ◽  
Optimistic Concurrency Control ◽  
Early Release ◽  
Low Level

Abstract Transactional Memory (TM) is an alternative way of synchronizing concurrent accesses to shared memory by adopting the abstraction of transactions in place of low-level mechanisms like locks and barriers. TMs usually apply optimistic concurrency control to provide a universal and easy-to-use method of maintaining correctness. However, this approach performs a high number of aborts in high contention workloads, which can adversely affect performance. Optimistic TMs can cause problems when transactions contain irrevocable operations. Hence, pessimistic TMs were proposed to solve some of these problems. However, an important way of achieving efficiency in pessimistic TMs is to use early release. On the other hand, early release is seemingly at odds with opacity, the gold standard of TM safety properties, which does not allow transactions to make their state visible until they commit. In this paper we propose a proof technique that makes it possible to demonstrate that a TM with early release can be opaque as long as it prevents inconsistent views.

scholarly journals Neuroimmune Response Mediated by Cytokines in Natural Scrapie after Chronic Dexamethasone Treatment

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 204
Author(s):  
Isabel M. Guijarro ◽  
Moisés Garcés ◽  
Pol Andrés-Benito ◽  
Belén Marín ◽  
Alicia Otero ◽  
...  
Keyword(s):  
Prion Diseases ◽  
Global Approach ◽  
Profile Data ◽  
Dexamethasone Treatment ◽  
New Approach ◽  
Complex Interactions ◽  
Natural Scrapie ◽  
Anti Inflammatory

The actual role of prion protein-induced glial activation and subsequent cytokine secretion during prion diseases is still incompletely understood. The overall aim of this study is to assess the effect of an anti-inflammatory treatment with dexamethasone on different cytokines released by neuroglial cells that are potentially related to neuroinflammation in natural scrapie. This study emphasizes the complex interactions existent among several pleiotropic neuromodulator peptides and provides a global approach to clarify neuroinflammatory processes in prion diseases. Additionally, an impairment of communication between microglial and astroglial populations mediated by cytokines, mainly IL-1, is suggested. The main novelty of this study is that it is the first one assessing in situ neuroinflammatory activity in relation to chronic anti-inflammatory therapy, gaining relevance because it is based on a natural model. The cytokine profile data would suggest the activation of some neurotoxicity-associated route. Consequently, targeting such a pathway might be a new approach to modify the damaging effects of neuroinflammation.

scholarly journals Parallel programming technologies on computer complexes

2020 ◽  
Vol 30 (3) ◽  
pp. 28-33 ◽  
Author(s):  
S. A. Pryadko ◽  
A. Yu. Troshin ◽  
V. D. Kozlov ◽  
A. E. Ivanov
Keyword(s):  
Parallel Programming ◽  
Shared Memory ◽  
Programming Language ◽  
Operating Systems ◽  
Distributed Memory ◽  
Programming Models ◽  
Writing Programs ◽  
Advantages And Disadvantages ◽  
C Programming Language ◽  
C Programming

The article describes various options for speeding up calculations on computer systems. These features are closely related to the architecture of these complexes. The objective of this paper is to provide necessary information when selecting the capability for the speeding process of solving the computation problem. The main features implemented using the following models are described: programming in systems with shared memory, programming in systems with distributed memory, and programming on graphics accelerators (video cards). The basic concept, principles, advantages, and disadvantages of each of the considered programming models are described. All standards for writing programs described in the article can be used both on Linux and Windows operating systems. The required libraries are available and compatible with the C/C++ programming language. The article concludes with recommendations on the use of a particular technology, depending on the type of task to be solved.

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