TY - CHAP A1 - Salem, Farouk A1 - Schütt, Thorsten A1 - Schintke, Florian A1 - Reinefeld, Alexander T1 - Scheduling Data Streams for Low Latency and High Throughput on a Cray XC40 Using Libfabric T2 - CUG Conference Proceedings N2 - Achieving efficient many-to-many communication on a given network topology is a challenging task when many data streams from different sources have to be scattered concurrently to many destinations with low variance in arrival times. In such scenarios, it is critical to saturate but not to congest the bisectional bandwidth of the network topology in order to achieve a good aggregate throughput. When there are many concurrent point-to-point connections, the communication pattern needs to be dynamically scheduled in a fine-grained manner to avoid network congestion (links, switches), overload in the node’s incoming links, and receive buffer overflow. Motivated by the use case of the Compressed Baryonic Matter experiment (CBM), we study the performance and variance of such communication patterns on a Cray XC40 with different routing schemes and scheduling approaches. We present a distributed Data Flow Scheduler (DFS) that reduces the variance of arrival times from all sources at least 30 times and increases the achieved aggregate bandwidth by up to 50%. Y1 - 2019 ER - TY - CHAP A1 - Hartung, Marc A1 - Schintke, Florian A1 - Schütt, Thorsten T1 - Pinpoint Data Races via Testing and Classification T2 - 2019 IEEE International Symposium on Software Reliability Engineering Workshops (ISSREW); 3rd International Workshop on Software Faults (IWSF 2019) Y1 - 2019 U6 - https://doi.org/10.1109/ISSREW.2019.00100 SP - 386 EP - 393 ER - TY - CHAP A1 - Gholami, Masoud A1 - Schintke, Florian T1 - Multilevel Checkpoint/Restart for Large Computational Jobs on Distributed Computing Resources T2 - 2019 IEEE 38th Symposium on Reliable Distributed Systems (SRDS) Y1 - 2019 U6 - https://doi.org/10.1109/SRDS47363.2019.00025 SP - 143 EP - 152 ER - TY - CHAP A1 - Skrzypczak, Jan A1 - Schintke, Florian A1 - Schütt, Thorsten T1 - Linearizable State Machine Replication of State-Based CRDTs without Logs T2 - Proceedings of the 2019 ACM Symposium on Principles of Distributed Computing, PODC 2019 N2 - General solutions of state machine replication have to ensure that all replicas apply the same commands in the same order, even in the presence of failures. Such strict ordering incurs high synchronization costs due to the use of distributed consensus or a leader. This paper presents a protocol for linearizable state machine replication of conflict-free replicated data types (CRDTs) that neither requires consensus nor a leader. By leveraging the properties of state-based CRDTs—in particular the monotonic growth of a join semilattice—synchronization overhead is greatly reduced. In addition, updates just need a single round trip and modify the state ‘in-place’ without the need for a log. Furthermore, the message size overhead for coordination consists of a single counter per message. While reads in the presence of concurrent updates are not wait-free without a coordinator, we show that more than 97 % of reads can be handled in one or two round trips under highly concurrent accesses. Our protocol achieves high throughput without auxiliary processes such as command log management or leader election. It is well suited for all practical scenarios that need linearizable access on CRDT data on a fine-granular scale. Y1 - 2019 U6 - https://doi.org/10.1145/3293611.3331568 SP - 455 EP - 457 ER - TY - JOUR A1 - Skrzypczak, Jan A1 - Schintke, Florian A1 - Schütt, Thorsten T1 - Linearizable State Machine Replication of State-Based CRDTs without Logs JF - arXiv N2 - General solutions of state machine replication have to ensure that all replicas apply the same commands in the same order, even in the presence of failures. Such strict ordering incurs high synchronization costs caused by distributed consensus or by the use of a leader. This paper presents a protocol for linearizable state machine replication of conflict-free replicated data types (CRDTs) that neither requires consensus nor a leader. By leveraging the properties of state-based CRDTs - in particular the monotonic growth of a join semilattice - synchronization overhead is greatly reduced. In addition, updates just need a single round trip and modify the state `in-place' without the need for a log. Furthermore, the message size overhead for coordination consists of a single counter per message. While reads in the presence of concurrent updates are not wait-free without a coordinator, we show that more than 97% of reads can be handled in one or two round trips under highly concurrent accesses. Our protocol achieves high throughput without auxiliary processes like command log management or leader election. It is well suited for all practical scenarios that need linearizable access on CRDT data on a fine-granular scale. Y1 - 2019 ER - TY - CHAP A1 - Hartung, Marc A1 - Schintke, Florian T1 - Learned Clause Minimization in Parallel SAT Solvers T2 - Pragmatics of SAT 2019 N2 - Learned clauses minimization (LCM) let to performance improvements of modern SAT solvers especially in solving hard SAT instances. Despite the success of LCM approaches in sequential solvers, they are not widely incorporated in parallel SAT solvers. In this paper we explore the potential of LCM for parallel SAT solvers by defining multiple LCM approaches based on clause vivification, comparing their runtime in different SAT solvers and discussing reasons for performance gains and losses. Results show that LCM only boosts performance of parallel SAT solvers on a fraction of SAT instances. More commonly applying LCM decreases performance. Only certain LCM approaches are able to improve the overall performance of parallel SAT solvers. Y1 - 2019 UR - http://www.pragmaticsofsat.org/2019/ SP - 1 EP - 11 ER - TY - JOUR A1 - Salem, Farouk A1 - Schintke, Florian A1 - Schütt, Thorsten A1 - Reinefeld, Alexander T1 - Improving the throughput of a scalable FLESnet using the Data-Flow Scheduler JF - CBM Progress Report 2018 Y1 - 2019 SN - 978-3-9815227-6-1 U6 - https://doi.org/10.15120/GSI-2019-01018 SP - 149 EP - 150 ER - TY - CHAP A1 - Weinhold, Carsten A1 - Lackorzynski, Adam A1 - Bierbaum, Jan A1 - Küttler, Martin A1 - Planeta, Maksym A1 - Weisbach, Hannes A1 - Hille, Matthias A1 - Härtig, Hermann A1 - Margolin, Alexander A1 - Sharf, Dror A1 - Levy, Ely A1 - Gak, Pavel A1 - Barak, Amnon A1 - Gholami, Masoud A1 - Schintke, Florian A1 - Schütt, Thorsten A1 - Reinefeld, Alexander A1 - Lieber, Matthias A1 - Nagel, Wolfgang T1 - FFMK: A Fast and Fault-Tolerant Microkernel-Based System for Exascale Computing T2 - Software for Exascale Computing - SPPEXA 2016-2019 Y1 - 2019 U6 - https://doi.org/10.1007/978-3-030-47956-5_16 SP - 483 EP - 516 PB - Springer ER -