IObuffering

IObuffering is a term used in computer science to describe performance degradation that arises from the buffering of input and output data within a system. It refers to a class of effects where buffering, caching, and delayed flushing interact with workload characteristics to produce higher tail latency and unpredictable throughput.

The term is informal and not tied to a single standard metric. It is used to describe problems appearing in databases, file systems, and streaming pipelines where buffering policies, such as large write-back caches, read-ahead, or network buffering, misalign with workload bursts, leading to delayed processing or bursty I/O.

Key mechanisms include multi-layer buffering: application-level buffers, OS page cache, filesystem buffers, device write caches, and network buffers. When buffers fill or flush policies trigger, the system may stall, causing latency spikes. Queuing and scheduling interactions can create long tails even when average throughput is adequate.

Impacts include degraded interactivity, service-level agreement violations, and increased power consumption. It is of particular concern for latency-sensitive services such as online databases, real-time analytics, and streaming platforms.

Mitigation strategies focus on tuning and policy changes: adjusting buffer sizes and flush frequency, using direct or unbuffered I/O where appropriate, enabling backpressure, employing tiered storage, and improving parallelism and I/O scheduling. Observability of buffering layers is essential to identify where IObuffering arises.

See also: I/O buffering, disk I/O scheduling, cache coherence, tail latency.