# Strange performance issue on 1.9.0-rc3

**URL:** <https://discourse.julialang.org/t/strange-performance-issue-on-1-9-0-rc3/98427>\
**Category:** Performance\
**Tags:** question, package\
**Created:** [May 7, 2023, 1:50am UTC](https://discourse.julialang.org/t/strange-performance-issue-on-1-9-0-rc3/98427 "2023-05-07T01:50:59Z")\
**Posts on this page:** 1\
**Showing post:** 7

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**Author:** ![MilesCranmer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/milescranmer/32/21070_2.png) [@MilesCranmer](https://discourse.julialang.org/u/MilesCranmer)\
**Post date:** [May 7, 2023, 10:20pm UTC](https://discourse.julialang.org/t/strange-performance-issue-on-1-9-0-rc3/98427/7 "2023-05-07T22:20:31Z")

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Okay I think I might have figured out the issue thanks to Cthulhu:

 ![image](https://global.discourse-cdn.com/julialang/original/3X/2/4/2493e1248bd1f6ef572d34c68cadfb57ad37d2d5.png)

I did not realize this, but apparently Julia does not perform multiple dispatch on keyword arguments? Is that (still) true?

> [@Force specialization on kwargs](https://discourse.julialang.org/t/force-specialization-on-kwargs/34789):
>
> If I have a function like this: f\_vararg(varargs::Int...) = tuple(varargs...) I can force specialization on varargs with either of the following: g\_vararg(varargs::Vararg{Int, N}) where {N} = tuple(varargs...) h\_vararg(varargs::Vararg{\<:Any, N}) where {N} = tuple(varargs...) Now suppose instead that I have a function like this: f\_kwarg(; kwargs...) = (; kwargs...) How can I force specialization on the keyword arguments?

If so then I suppose I need to specify this `result_type` as a normal argument, rather than a kwarg. Otherwise it thinks the return type is `Any`, because `result_type` could be anything.

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