# Innefficient paralellization? Need some help optimizing a simple dot product

**URL:** <https://discourse.julialang.org/t/innefficient-paralellization-need-some-help-optimizing-a-simple-dot-product/9723>\
**Category:** Performance\
**Tags:** question, parallel\
**Created:** [March 14, 2018, 10:34pm UTC](https://discourse.julialang.org/t/innefficient-paralellization-need-some-help-optimizing-a-simple-dot-product/9723 "2018-03-14T22:34:20Z")\
**Posts on this page:** 1\
**Showing post:** 30

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**Author:** ![tkoolen](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/tkoolen/32/1603_2.png) [@tkoolen](https://discourse.julialang.org/u/tkoolen)\
**Post date:** [March 23, 2018, 5:26pm UTC](https://discourse.julialang.org/t/innefficient-paralellization-need-some-help-optimizing-a-simple-dot-product/9723/30 "2018-03-23T17:26:11Z")

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Just a guess, but maybe this is [performance of captured variables in closures · Issue #15276 · JuliaLang/julia · GitHub](https://github.com/JuliaLang/julia/issues/15276) once again (the `@threads` macro creates a closure). See also see [Parallelizing for loop in the computation of a gradient - #7 by tkoolen](https://discourse.julialang.org/t/parallelizing-for-loop-in-the-computation-of-a-gradient/9154/7). Check the `code_warntype`.

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