src: handling v8 thread pool of zero #42524
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fix: nodejs#42523 Problem: If no platform worker exists, Node.js doesn't shut down when background tasks exist. It keeps waiting in `NodePlatform::DrainTasks`. Observation: It seems that Node.js used to use V8's `DefaultPlatform` implementation, which chooses a suitable default value in case that `--v8-pool-size=0` is given as a command-line option. However, Node.js currently uses its own v8::Platform implementation, `NodePlatform`. It doesn't have the logic to handle the case. I referred to nodejs#4344 to track the issue.
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| if (uv_cpu_info(&cpu_info, &count) == 0) { | ||
| uv_free_cpu_info(cpu_info, count); | ||
| thread_pool_size = count - 1; | ||
| } | ||
| } |
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I suggest waiting for the upgrade to libuv 1.44 and replacing this with uv_available_parallelism(), it's specifically for use cases such as this one.
uv_cpu_info() isn't really appropriate because it doesn't know how many processors are available to the process, only how many are online.
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uv_available_parallelism() looks more suited to this case indeed. I'll wait for the upgrade to land.
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Resolved: #42523
Problem:
If no platform worker exists, Node.js doesn't shut down when background
tasks scheduled exist. It keeps waiting in
NodePlatform::DrainTasks.Observation:
It seems that Node.js used V8's
DefaultPlatformimplementation a longtime ago, which chooses a suitable default value in case
--v8-pool-size=0is given as a command-line option. However, Node.js currently uses its
own v8::Platform implementation,
NodePlatform. It seems not to havethe logic to handle the case.
I referred to #4344 to track the issue.