Paper Info
Title
Birds of a Feather Flock Together: Scaling RDMA RPCs with Flock
Abstract
ABSTRACTRDMA-capable networks are gaining traction with datacenter deployments due to their high throughput, low latency, CPU efficiency, and advanced features, such as remote memory operations. However, efficiently utilizing RDMA capability in a common setting of high fan-in, fan-out asymmetric network topology is challenging. For instance, using RDMA programming features comes at the cost of connection scalability, which does not scale with increasing cluster size. To address that, several works forgo some RDMA features by only focusing on conventional RPC APIs. In this work, we strive to exploit the full capability of RDMA, while scaling the number of connections regardless of the cluster size. We present Flock, a communication framework for RDMA networks that uses hardware provided reliable connection. Using a partially shared model, Flock departs from the conventional RDMA design by enabling connection sharing among threads, which provides significant performance improvements contrary to the widely held belief that connection sharing deteriorates performance. At its core, Flock uses a connection handle abstraction for connection multiplexing; a new coalescing-based synchronization approach for efficient network utilization; and a load-control mechanism for connections with symbiotic send-recv scheduling, which reduces the synchronization overheads associated with connection sharing along with ensuring fair utilization of network connections. We demonstrate the benefits for a distributed transaction processing system and an in-memory index, where it outperforms other RPC systems by up to 88% and 50%, respectively, with significant reductions in median and tail latency.
Year
DOI
Venue
2021
10.1145/3477132.3483576
SOSP
DocType
Citations 
PageRank 
Conference
0
0.34
References 
Authors
0
3
Name
Order
Citations
PageRank
Sumit Kumar Monga100.34
Sanidhya Kashyap212410.92
Changwoo Min329429.89