Orinoco: Young Generation Garbage Collection

2 days ago

JavaScript objects in V8 are managed on a heap by V8’s garbage collector, which reduces pause times and memory consumption.
The parallel Scavenger is a new feature of Orinoco, V8's concurrent and parallel garbage collector.
V8 uses a generational heap with a nursery, intermediate, and old generation; objects move up after surviving collections.
Before V8 version 6.2, a single-threaded Cheney semispace copying collector was used for young generation collections.
The parallel Scavenger, introduced in v6.2, utilizes dynamic work stealing across threads for better performance.
An alternative parallel Mark-Evacuate algorithm was tested but had overhead due to separate lockstep phases.
The parallel Scavenger merges marking, copying, and pointer updating phases for improved throughput and efficiency.
It utilizes per-page remembered sets for root distribution and work stealing for load balancing.
Performance improvements include 20%–50% reductions in young generation garbage collection time on benchmarks.
The parallel Scavenger is optimized for modern multi-core environments, including Arm big.LITTLE architectures.

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