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The Lock-free k-LSM Relaxed Priority Queue [article]

Martin Wimmer, Jakob Gruber, Jesper Larsson Träff, Philippas Tsigas
2015 arXiv   pre-print
We experimentally compare our priority queue to recent state-of-the-art lock-free priority queues, both with relaxed and non-relaxed semantics, showing high performance and good scalability of our approach  ...  We present a new, lock-free priority queue that relaxes the delete-min operation so that it is allowed to delete any of the ρ+1 smallest keys, where ρ is a runtime configurable parameter.  ...  Evaluation We now compare our lock-free k-priority queue to the recent, relaxed lock-free priority queues by Alistarh et al. [2] and Wimmer et al.  ... 
arXiv:1503.05698v1 fatcat:7g5wbzeyo5eypffi266wr4ta7e

The lock-free k-LSM relaxed priority queue

Martin Wimmer, Jakob Gruber, Jesper Larsson Träff, Philippas Tsigas
2015 SIGPLAN notices  
We present a new, concurrent, lock-free priority queue that relaxes the delete-min operation to allow deletion of any of the ρ + 1 smallest keys instead of only a minimal one, where ρ is a parameter that  ...  We compare to state-ofthe-art lock-free priority queues with both relaxed and non-relaxed semantics, showing high performance and good scalability of our approach.  ...  Experimental Evaluation and Comparison We have compared our lock-free k-priority queue to a state-ofthe-art lock-free priority queue by Lindén and Jonsson [5] , and to the recent relaxed lock-free priority  ... 
doi:10.1145/2858788.2688547 fatcat:emmtduqidvczhlmct56c6yphcu

The lock-free k-LSM relaxed priority queue

Martin Wimmer, Jakob Gruber, Jesper Larsson Träff, Philippas Tsigas
2015 Proceedings of the 20th ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming - PPoPP 2015  
We present a new, concurrent, lock-free priority queue that relaxes the delete-min operation to allow deletion of any of the ρ + 1 smallest keys instead of only a minimal one, where ρ is a parameter that  ...  We compare to state-ofthe-art lock-free priority queues with both relaxed and non-relaxed semantics, showing high performance and good scalability of our approach.  ...  Experimental Evaluation and Comparison We have compared our lock-free k-priority queue to a state-ofthe-art lock-free priority queue by Lindén and Jonsson [5] , and to the recent relaxed lock-free priority  ... 
doi:10.1145/2688500.2688547 dblp:conf/ppopp/0003GTT15 fatcat:t5g2mgajqfflpdmkqhe5afppxq

Benchmarking Concurrent Priority Queues: Performance of k-LSM and Related Data Structures [article]

Jakob Gruber, Jesper Larsson Träff, Martin Wimmer
2016 arXiv   pre-print
Our benchmark code and k-LSM priority queue are publicly available to foster future comparison.  ...  While we can show superior throughput and scalability for our own k-LSM priority queue for the uniform key distribution, the picture changes drastically for other distributions, both with respect to achieved  ...  THE K-LSM PRIORITY QUEUE The k-LSM [7, 26] is a lock-free, linearizable, relaxed priority queue consisting of a global component called the Shared LSM (SLSM), and a thread-local component called the  ... 
arXiv:1603.05047v1 fatcat:h73h2oyibbaj3d33gjhpvavdzu

The Contention Avoiding Concurrent Priority Queue [chapter]

Konstantinos Sagonas, Kjell Winblad
2017 Lecture Notes in Computer Science  
This bottleneck is the motivation for some recently proposed priority queues with more relaxed semantics.  ...  Linearizable concurrent priority queues with traditional semantics suffer from an inherent sequential bottleneck in the head of the queue.  ...  All the above relaxed priority queues (MultiQueue, SprayList, Hybrid k and k-LSM) utilize relaxations to avoid contention in DELMIN operations.  ... 
doi:10.1007/978-3-319-52709-3_23 fatcat:4gkjmccaynh33k7izzjr7dsdra

Engineering MultiQueues: Fast Relaxed Concurrent Priority Queues [article]

Marvin Williams, Peter Sanders, Roman Dementiev
2021 arXiv   pre-print
We employ a seemingly paradoxical technique of "wait-free locking" that might be of more general interest to convert sequential data structures to relaxed concurrent data structures.  ...  In this paper, we introduce MultiQueues as a natural approach to relaxed priority queues based on multiple sequential priority queues.  ...  k-LSM [30] combines thread-local priority queues with a relaxed shared priority queue component. We use the variants with k = 256 (klsm256) and k = 1024 (klsm1024).  ... 
arXiv:2107.01350v2 fatcat:qs57dg4tyzfodfra4gxvhjqghe

Engineering MultiQueues: Fast Relaxed Concurrent Priority Queues

Marvin Williams, Peter Sanders, Roman Dementiev, Petra Mutzel, Rasmus Pagh, Grzegorz Herman
2021
We employ a seemingly paradoxical technique of "wait-free locking" that might be of more general interest to convert sequential data structures to relaxed concurrent data structures.  ...  In this paper, we introduce MultiQueues as a natural approach to relaxed priority queues based on multiple sequential priority queues.  ...  Beyond priority queues, it would be interesting to see whether our approach to "wait-free" locking can be used for other applications, e.g., for FIFOs.  ... 
doi:10.4230/lipics.esa.2021.81 fatcat:r4uqkrtpkfhmrepgukstgjbypu

The Lustre Storage Architecture [article]

Peter Braam
2019 arXiv   pre-print
This lengthy document often referred to as the "Lustre Book", contains a detailed outline of Lustre file system architecture, as it was created between 2001 and 2005, in accordance with the requirements  ...  blocks qos_freeblock_percent: same, but for percentage free Priorities are: blocks free, number of objects, percentage free. (11) aa_lov (include/linux/obd_lov.h) -We also collect QOS information on asynchronous  ...  The OST could maintain a priority queue to handle the requests. b) In other situations the clients could be promised only upto certain maximum bandwidth.  ... 
arXiv:1903.01955v1 fatcat:fuq664grqzcexcovxzd2n7f5ji

On achieving scalability through relaxation

Giorgi Nadiradze, Dan-Adrian Alistarh
2021
Specifically, in data structures such as priority queues, imposing strong semantics renders scalability impossible, since a correct implementation of the remove operation should return only the element  ...  We prove that the randomized implementations of relaxed data structures provide provable guarantees on the priority of the removed elements even under concurrency.  ...  We verify correctness by checking that the array contents are consistent with the number of executed operations at the end of the run; none of these experiments have resulted in erroneous outputs.  ... 
doi:10.15479/at:ista:10429 fatcat:kpvjvz72mzao5ntyv6m5rygbme

The Vessel Schedule Recovery Problem (VSRP) – A MIP model for handling disruptions in liner shipping

Berit D. Brouer, Jakob Dirksen, David Pisinger, Christian E.M. Plum, Bo Vaaben
2013 European Journal of Operational Research  
The first tentative results show that these factors influence the company profit, affecting significantly the performance of the deterministic solutions.  ...  In considering the interests of users and investors, the proposed model attempts to determine the number and locations of bike stations, the network structure of bike paths connected between the stations  ...  We expose the following relaxations of CARP pricing problem: partially elementary tours, NG-route relaxation (including a dynamic version), and k-loop-free pricing.  ... 
doi:10.1016/j.ejor.2012.08.016 fatcat:c27kagfnxnhjfbil2rydhjhomm

Distributed Metadata and Streaming Data Indexing as Scalable Filesystem Services

Qing Zheng
2021
This is especially the case when all the metadata synchronization andserialization work is coordinated by a small, fixed set of filesystem metadata servers as we see in many HPCplatforms today.  ...  Since scientific applications are typically non-interactive batch programs, the first theme of thisthesis is about taking advantage of knowledge about the system and scientific applications to drastically  ...  The scientist then submits the batch script to a job queue. A workload manager monitors the queue and is responsible for launching the job when resources become available.  ... 
doi:10.1184/r1/14546973.v1 fatcat:3vk3ds4fqrdnni2onwhqbvdtv4

Gulustan-Black Sea Scientific Journal of Academic Research

Namig Isazade
2020 Zenodo  
therapy, proprioception and relaxation sessions.  ...  Friction forces were considered sufficient for counteract the locking force of the wheels, thus it was not included in calculations.  ...  As a message-oriented middleware, it can process thousands of trusted transactions in a queue. AMQP is designed not to lose messages, since messages can be transmitted using TCP or UDP.  ... 
doi:10.5281/zenodo.3780434 fatcat:wbushaip7zdpfamasqud2perly

TIMING OF SURGICAL INTERVENTION AFTER VENTRICULAR SEPTAL RUPTURE

Guliko Kiliptari
2019 Black Sea scientific journal of academic research  
The Colour Doppler was demonstrated of flow across the septum and left to rigt shunt.  ...  The case reflects the important problem after myocardial infarction , ventricular septal rupture and challenges the timing of intervention Patient 70 year old,male,caucasion was admitted in our hospital  ...  therapy, proprioception and relaxation sessions.  ... 
doi:10.36962/gbssjar17 fatcat:2ercpkiyzvbdbnwswrzqwnypzu

Business Model With Alternative Scenarios (D4.1)

Jakob Luettgau, Julian Kunkel, Jens Jensen, Bryan Lawrence
2017 Zenodo  
This report summarizes the work on requirements and business models for the storage infrastructure within weather and climate data centres (although much of the work has wider applicability).  ...  The body of the work is an integrated graph-based approach to modelling costs, resilience and performance for storage systems.  ...  ), or to help the customer avoid vendor lock-in.  ... 
doi:10.5281/zenodo.1228749 fatcat:fdwtwtfcwjhhbkiusam6njs26a

Shell activity logging and auditing in exercise environments of security Lectures using OSS

Florian Pritz, Thomas Grechenig, Florian Fankhauser
2019
An auditor can use the audit log data to verify that the organisations systems, and the information that is stored on them, were used in accordance with the requirements of the relevant regulations.  ...  The implementation is evaluated and tested to show that the identified requirements are fulfilled. A central element of the concept is the recording of all [...]  ...  Acknowledgements I wish to thank Thomas Grechenig for supporting my work as my advisor and making it possible in the first place.  ... 
doi:10.34726/hss.2019.65385 fatcat:f2xbvw7onvekbanrudeabcy3pa
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