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Recommend @spawn over @async #44667

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Merged
vtjnash merged 2 commits into from
Mar 21, 2022
Merged

Recommend @spawn over @async #44667

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14eca7f
Recommend `@spawn` over `@async` unconditionally
tkf Mar 18, 2022
0821d84
Update base/task.jl
tkf Mar 21, 2022
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8 changes: 8 additions & 0 deletions base/task.jl
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Expand Up @@ -467,6 +467,14 @@ Values can be interpolated into `@async` via `\$`, which copies the value direct
constructed underlying closure. This allows you to insert the _value_ of a variable,
isolating the asynchronous code from changes to the variable's value in the current task.

!!! warning
It is strongly encouraged to favor `Threads.@spawn` over `@async` always **even when no
parallelism is required** especially in publicly distributed libraries. This is
because a use of `@async` disables the migration of the *parent* task across worker
threads in the current implementation of Julia. Thus, seemingly innocent use of
`@async` in a library function can have a large impact on the performance of very
different parts of user applications.

!!! compat "Julia 1.4"
Interpolating values via `\$` is available as of Julia 1.4.
"""
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