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GeezerVison is showing github.com — src: handling v8 thread pool of zero by daeyeon · Pull Request #42524 · nodejs/node

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@daeyeon

@daeyeon daeyeon commented Mar 30, 2022

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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 DefaultPlatform implementation a long
time ago, which chooses a suitable default value in case --v8-pool-size=0
is given as a command-line option. However, Node.js currently uses its
own v8::Platform implementation, NodePlatform. It seems not to have
the logic to handle the case.

I referred to #4344 to track the issue.

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@daeyeon
src: handling v8 thread pool of zero
9fd2df7 
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.
@nodejs-github-bot nodejs-github-bot added c++ Issues and PRs that require attention from people who are familiar with C++. needs-ci PRs that need a full CI run. labels Mar 30, 2022
@daeyeon
doc: fix lint-md ci error
182a83f
bnoordhuis
bnoordhuis reviewed Mar 30, 2022
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Comment thread src/node_platform.cc
Comment on lines +53 to +57
if (uv_cpu_info(&cpu_info, &count) == 0) {
uv_free_cpu_info(cpu_info, count);
thread_pool_size = count - 1;
}
}

@bnoordhuis bnoordhuis Mar 30, 2022

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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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@daeyeon daeyeon Mar 31, 2022

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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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@Trott
Trott force-pushed the main branch from 2d76238 to ca3ed36 Compare November 12, 2022 01:49
@daeyeon daeyeon mentioned this pull request Nov 19, 2022
src: set an appropriate thread pool size if given --v8-pool-size=0 #45513
Merged
@daeyeon daeyeon closed this Nov 21, 2022
@daeyeon
daeyeon deleted the master.node-220330.Wed-20.01 branch November 21, 2022 03:53
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Run worker threads with --v8-pool-size=0

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@daeyeon @bnoordhuis @nodejs-github-bot
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