| 1. |
- Canini, Marco, et al.
(författare)
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Fault Prediction in Distributed Systems Gone Wild
- 2010
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Ingår i: Proceedings of The 4th ACM SIGOPS/SIGACT Workshop on Large Scale Distributed Systems and Middleware. - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450304061 ; , s. -11
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Konferensbidrag (refereegranskat)abstract
- We consider the problem of predicting faults in deployed, large-scale distributed systems that are heterogeneous and federated. Motivated by the importance of ensuring reliability of the services these systems provide, we argue that the key step in making these systems reliable is the need to automatically predict faults. For example, doing so is vital for avoiding Internet-wide outages that occur due to programming errors or misconfigurations.
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| 2. |
- Novakovic, Dejan, et al.
(författare)
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DeepDive : Transparently Identifying and Managing Performance Interference in Virtualized Environments
- 2013
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Ingår i: Proceedings of The 2013 USENIX Annual Technical Conference.
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Konferensbidrag (refereegranskat)abstract
- We describe the design and implementation of Deep-Dive, a system for transparently identifying and managing performance interference between virtual machines (VMs) co-located on the same physical machine in Infrastructure-as-a-Service cloud environments. DeepDive successfully addresses several important challenges, including the lack of performance information from applications, and the large overhead of detailed interference analysis. We first show that it is possible to use easily-obtainable, low-level metrics to clearly discern when interference is occurring and what resource is causing it. Next, using realistic workloads, we show that DeepDive quickly learns about interference across co-located VMs. Finally, we show DeepDive’s ability to deal efficiently with interference when it is detected, by using a low-overhead approach to identifying a VM placement that alleviates interference.
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| 3. |
- Vasic, Nedeljko, et al.
(författare)
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DejaVu : Accelerating Resource Allocation in Virtualized Environments
- 2012
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Ingår i: Proceedings of the Seventeenth International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS). - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450307598 ; , s. -436
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Konferensbidrag (refereegranskat)abstract
- Effective resource management of virtualized environments is a challenging task. State-of-the-art management systems either rely on analytical models or evaluate resource allocations by running actual experiments. However, both approaches incur a significant overhead once the workload changes. The former needs to recalibrate and re-validate models, whereas the latter has to run a new set of experiments to select a new resource allocation. During the adaptation period, the system may run with an inefficient configuration.
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| 4. |
- Vasic, Nedeljko, et al.
(författare)
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Identifying and Using Energy-Critical Paths
- 2011
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Ingår i: Proceedings of The 7th International Conference on emerging Networking EXperiments and Technologies (ACM CoNEXT). - New York, NY, USA : Association for Computing Machinery (ACM). - 9781450310413
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Konferensbidrag (refereegranskat)abstract
- The power consumption of the Internet and datacenter networks is already significant, and threatens to shortly hit the power delivery limits while the hardware is trying to sustain ever-increasing traffic requirements. Existing energy-reduction approaches in this domain advocate recomputing network configuration with each substantial change in demand. Unfortunately, computing the minimum network subset is computationally hard and does not scale. Thus, the network is forced to operate with diminished performance during the recomputation periods. In this paper, we propose REsPoNse, a framework which overcomes the optimality-scalability trade-off. The insight in REsPoNse is to identify a few energy-critical paths off-line, install them into network elements, and use a simple online element to redirect the traffic in a way that enables large parts of the network to enter a low-power state. We evaluate REsPoNse with real network data and demonstrate that it achieves the same energy savings as the existing approaches, with marginal impact on network scalability and application performance.
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| 5. |
- Anderson, Thomas, et al.
(författare)
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Assise: Performance and Availability via Client-local NVM in a Distributed File System
- 2020
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Konferensbidrag (refereegranskat)abstract
- The adoption of low latency persistent memory modules (PMMs) upends the long-established model of remote storage for distributed file systems. Instead, by colocating computation with PMM storage, we can provide applications with much higher IO performance, sub-second application failover, and strong consistency. To demonstrate this, we built the Assise distributed file system, based on a persistent, replicated coherence protocol that manages client-local PMM as a linearizable and crash-recoverable cache between applications and slower (and possibly remote) storage. Assise maximizes locality for all file IO by carrying out IO on process-local, socket-local, and client-local PMM whenever possible. Assise minimizes coherence overhead by maintaining consistency at IO operation granularity, rather than at fixed block sizes.We compare Assise to Ceph/BlueStore, NFS, and Octopus on a cluster with Intel Optane DC PMMs and SSDs for common cloud applications and benchmarks, such as LevelDB, Postfix, and FileBench. We find that Assise improves write latency up to 22x, throughput up to 56x, fail-over time up to 103x, and scales up to 6x better than its counterparts, while providing stronger consistency semantics.
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| 6. |
- Bachwani, Rekha, et al.
(författare)
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Sahara : Guiding the Debugging of Failed Software Upgrades
- 2011
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Ingår i: Proceedings of the 27th IEEE International Conference on Software Maintenance. - : IEEE conference proceedings. - 9781457706639 ; , s. -272
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Konferensbidrag (refereegranskat)abstract
- Today, debugging failed software upgrades is a long and tedious activity, as developers may have to consider large sections of code to locate the bug. We argue that failed upgrade debugging can be simplified by exploiting the characteristics of upgrade problems to prioritize the set of routines to consider. In particular, previous work has shown that differences between the computing environment in the developer's and users' sites cause most upgrade problems. Based on this observation, we design and implement Sahara, a system that identifies the aspects of the environment that are most likely the culprits of the misbehavior, finds the subset of routines that relate to those aspects, and selects an even smaller subset of routines to debug first. We evaluate Sahara for three real upgrade problems with the OpenSSH suite, one synthetic problem with the SQLite database, and one synthetic problem with the uServer Web server. Our results show that the system produces accurate recommendations comprising only a small number of routines.
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| 7. |
- Barbette, Tom, 1990-, et al.
(författare)
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A High-Speed Load-Balancer Design with Guaranteed Per-Connection-Consistency
- 2020
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Ingår i: Proceedings of the 17th USENIX Symposium on Networked Systems Design and Implementation, NSDI 2020. - Santa Clara, CA, USA : USENIX Association. ; , s. 667-683
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Konferensbidrag (refereegranskat)abstract
- Large service providers use load balancers to dispatch millions of incoming connections per second towards thousands of servers. There are two basic yet critical requirements for a load balancer: uniform load distribution of the incoming connections across the servers and per-connection-consistency (PCC), i.e., the ability to map packets belonging to the same connection to the same server even in the presence of changes in the number of active servers and load balancers. Yet, meeting both these requirements at the same time has been an elusive goal. Today's load balancers minimize PCC violations at the price of non-uniform load distribution.This paper presents Cheetah, a load balancer that supports uniform load distribution and PCC while being scalable, memory efficient, resilient to clogging attacks, and fast at processing packets. The Cheetah LB design guarantees PCC for any realizable server selection load balancing mechanism and can be deployed in both a stateless and stateful manner, depending on the operational needs. We implemented Cheetah on both a software and a Tofino-based hardware switch. Our evaluation shows that a stateless version of Cheetah guarantees PCC, has negligible packet processing overheads, and can support load balancing mechanisms that reduce the flow completion time by a factor of 2–3×.
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| 8. |
- Barbette, Tom, 1990-, et al.
(författare)
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Cheetah : A High-Speed Programmable Load-Balancer Framework with Guaranteed Per-Connection-Consistency
- 2022
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Ingår i: IEEE/ACM Transactions on Networking. - : Institute of Electrical and Electronics Engineers (IEEE). - 1063-6692 .- 1558-2566. ; 30:1, s. 354-367
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Tidskriftsartikel (refereegranskat)abstract
- Large service providers use load balancers to dispatch millions of incoming connections per second towards thousands of servers. There are two basic yet critical requirements for a load balancer: uniform load distribution of the incoming connections across the servers, which requires to support advanced load balancing mechanisms, and per-connection-consistency (PCC), i.e, the ability to map packets belonging to the same connection to the same server even in the presence of changes in the number of active servers and load balancers. Yet, simultaneously meeting these requirements has been an elusive goal. Today's load balancers minimize PCC violations at the price of non-uniform load distribution. This paper presents Cheetah, a load balancer that supports advanced load balancing mechanisms and PCC while being scalable, memory efficient, fast at processing packets, and offers comparable resilience to clogging attacks as with today's load balancers. The Cheetah LB design guarantees PCC for any realizable server selection load balancing mechanism and can be deployed in both stateless and stateful manners, depending on operational needs. We implemented Cheetah on both a software and a Tofino-based hardware switch. Our evaluation shows that a stateless version of Cheetah guarantees PCC, has negligible packet processing overheads, and can support load balancing mechanisms that reduce the flow completion time by a factor of 2-3 ×.
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| 9. |
- Barbette, Tom, 1990-, et al.
(författare)
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RSS++: load and state-aware receive side scaling
- 2019
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Ingår i: Proceedings of the 15th International Conference on emerging Networking EXperiments and Technologies. - Orlando, FL, USA : Association for Computing Machinery (ACM). - 9781450369985
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Konferensbidrag (refereegranskat)abstract
- While the current literature typically focuses on load-balancing among multiple servers, in this paper, we demonstrate the importance of load-balancing within a single machine (potentially with hundreds of CPU cores). In this context, we propose a new load-balancing technique (RSS++) that dynamically modifies the receive side scaling (RSS) indirection table to spread the load across the CPU cores in a more optimal way. RSS++ incurs up to 14x lower 95th percentile tail latency and orders of magnitude fewer packet drops compared to RSS under high CPU utilization. RSS++ allows higher CPU utilization and dynamic scaling of the number of allocated CPU cores to accommodate the input load, while avoiding the typical 25% over-provisioning. RSS++ has been implemented for both (i) DPDK and (ii) the Linux kernel. Additionally, we implement a new state migration technique, which facilitates sharding and reduces contention between CPU cores accessing per-flow data. RSS++ keeps the flow-state by groups that can be migrated at once, leading to a 20% higher efficiency than a state of the art shared flow table.
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| 10. |
- Barbette, Tom, 1990-, et al.
(författare)
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Stateless CPU-aware datacenter load-balancing
- 2020
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Ingår i: Poster: Stateless CPU-aware datacenter load-balancing. - New York, NY, USA : Association for Computing Machinery (ACM). ; , s. 548-549
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Konferensbidrag (refereegranskat)abstract
- Today, datacenter operators deploy Load-balancers (LBs) to efficiently utilize server resources, but must over-provision server resources (by up to 30%) because of load imbalances and the desire to bound tail service latency. We posit one of the reasons for these imbalances is the lack of per-core load statistics in existing LBs. As a first step, we designed CrossRSS, a CPU core-aware LB that dynamically assigns incoming connections to the least loaded cores in the server pool. CrossRSS leverages knowledge of the dispatching by each server's Network Interface Card (NIC) to specific cores to reduce imbalances by more than an order of magnitude compared to existing LBs in a proof-of-concept datacenter environment, processing 12% more packets with the same number of cores.
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