BBQ: A Block-based Bounded Queue for Exchanging Data and Profiling

Concurrent bounded queues have been widely used for exchanging data and profiling in operating systems, databases, and multithreaded applications. The performance of state-of-the-art queues is limited by the interference between multiple enqueues (enq-enq), multiple dequeues (deq-deq), or enqueues and dequeues (enq-deq), negatively affecting their latency and scalability. Although some existing designs employ optimizations to reduce deq-deq and enq-enq interference, they often neglect the enq-deq case. In fact, such partial optimizations may inadvertently increase interference elsewhere and result in performance degradation.

We present Block-based Bounded Queue (BBQ), a novel ringbuffer design that splits the entire buffer into multiple blocks. This eliminates enq-deq interference on concurrency control variables when producers and consumers operate on different blocks. Furthermore, the block-based design is amenable to existing optimizations, e.g., using the more scalable fetch-and-add instruction. Our evaluation shows that BBQ outperforms several industrial ringbuffers. For example, in single-producer/single-consumer micro-benchmarks, BBQ yields 11.3x to 42.4x higher throughput than the ringbuffers from Linux kernel, DPDK, Boost, and Folly libraries. In real-world scenarios, BBQ achieves up to 1.5x, 50.5x, and 11.1x performance improvements in benchmarks of DPDK, Linux io_uring, and Disruptor, respectively. We verified and optimized BBQ on weak memory models with a model-checking-based framework.