vmMemoryLimit

• 类型: string | number
• 默认值: 1 / 最大线程数

此选项仅影响 vmForks 和 vmThreads 线程池。

指定工作线程被回收之前的内存限制。

By default, the total system memory is split evenly between workers. By increasing maxWorkers, workers have less memory available, so they're recycled more often.

This value heavily depends on your environment, so it's better to specify it manually instead of relying on the default.

Recycling exists because VM contexts leak memory: a worker's memory usage grows with every test file it runs, so a worker cannot live forever. The limit is a trade-off:

• A low limit recycles workers frequently. In the vmThreads pool this is expensive, because destroying a worker thread runs a full garbage collection over the worker's memory and competes with running tests for the process' shared background threads. The vmForks pool recycles workers by letting the child process exit, which makes frequent recycling much cheaper there.
• A high limit lets workers accumulate memory. When the combined memory usage of all workers approaches what the machine can hold, every pool slows down.

提示

该实现基于 Jest 的 workerIdleMemoryLimit。

可以通过多种不同的方式指定限制，无论结果是什么，Math.floor 都用于将其转换为整数值：

• <= 1 - 该值假定为系统内存的百分比。所以 0.5 将 worker 的内存限制设置为系统总内存的一半。
• \> 1 - 假设是固定字节值。由于之前的规则，如果你想要 1 字节的值（我不知道为什么），你可以使用 1.1。
• 有单位时
  • 50% - 如上，占系统总内存的百分比
  • 100KB, 65MB, 等 - 用单位表示固定的内存限制
    • K / KB - 千字节 (x1000)
    • KiB - 千字节 (x1024)
    • M / MB- 千字节
    • MiB - 兆字节
    • G / GB - 千兆字节
    • GiB - 千兆字节

注意

基于百分比的内存限制 在 Linux CircleCI 环境下无效，因该系统会误报内存总量。