lcore

Lcore is a term used in computing to denote a logical processor core, as distinct from a physical core. It is commonly employed to describe the unit of execution presented by a CPU to the operating system or software, especially in environments that expose multiple hardware threads per physical core.

In modern CPUs that support hyper-threading or simultaneous multithreading, a single physical core can provide more than one logical core. The operating system scheduler may treat these logical cores as separate execution contexts, allowing more concurrent threads than there are physical cores. The mapping between physical cores and logical cores is managed by the processor and the system, and performance can vary depending on workload characteristics, cache usage, and thread affinity.

A notable usage of the term appears in data plane and high-performance networking software. For example, the Data Plane Development Kit (DPDK) uses lcore to refer to the logical cores that run poll loops and processing tasks. Developers assign specific work to particular lcore IDs, and APIs exist to query, pin, and manage these cores to optimize throughput and latency. This convention helps separate the concepts of physical hardware and the software-visible execution units.

In broader systems contexts, lcore is encountered in performance tuning, virtualization, and parallel programming, where distinguishing between physical and logical cores aids in scheduling strategy, resource allocation, and bottleneck analysis. The term remains a foundational concept for understanding modern multi-core architectures.