JuliaInterop / JuliaInterop/JavaCall.jl
JULIA_COPY_STACKS=1 disable threading
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- Dominant language
- Julia
- Stars
- 125
- Forks
- 53
- PR merge metrics
- No merged PRs in 30d
Description
This upstream issue: https://github.com/JuliaLang/julia/issues/47591 is still current.
It would be good to (highly) warn the user about this. It is very difficult and takes a lot of time to get to the source of the bug, we must realize that:
- there is a slowdown
- multithreading is disabled even if Threads.nthreads() != 1
- it comes from JULIA_COPY_STACKS
- it comes from JavaCall
I don't know if this is the case for all systems though. My versioninfo:
julia> versioninfo()
Julia Version 1.11.5
Commit 760b2e5b739 (2025-04-14 06:53 UTC)
Build Info:
Official https://julialang.org/ release
Platform Info:
OS: Linux (x86_64-linux-gnu)
CPU: 16 × AMD Ryzen 7 8840HS w/ Radeon 780M Graphics
WORD_SIZE: 64
LLVM: libLLVM-16.0.6 (ORCJIT, znver3)
Threads: 16 default, 0 interactive, 8 GC (on 16 virtual cores)
Environment:
JULIA_COPY_STACKS = 1
Contributor guide
No contributing guide indexed for this repository
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with upstream Julia issue 47591 and inspect JavaCall's handling of JULIA_COPY_STACKS, then verify the reported slowdown and threading behavior. Done means users receive a clear warning identifying the slowdown, disabled multithreading, JULIA_COPY_STACKS, and JavaCall as the cause where applicable.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- java, julia
- Domain
- backend, performance
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100