# Losing performance when adding function to a package?
**URL:** https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533
**Category:** New to Julia
**Created:** [April 25, 2019, 9:51pm UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533 "2019-04-25T21:51:04Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)
#### Post date: [April 25, 2019, 9:51pm UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533/1 "2019-04-25T21:51:05Z")
Hey guys!
Basically I have a function which I use to read data. If I use this function directly inside of Julia ie. by compiling it as a function directly, using BenchmarkTools it runs in about 350 ms, but if I put it into a package instead and then load this package, it takes 150 ms longer, so 500 ms.
This of course is not a huge difference, but still in theory about 1/3 performance loss. Could someone explain to me why this would happen?
Kind regards
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### Author:  [@non-Jedi](https://discourse.julialang.org/u/non-Jedi)
#### Post date: [April 25, 2019, 10:30pm UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533/2 "2019-04-25T22:30:34Z")
Could you give a self-contained example of a function demonstrating this property please?
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### Author:  [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)
#### Post date: [April 26, 2019, 7:10am UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533/3 "2019-04-26T07:10:58Z")
Will try to do so later today, seems like it is not expected behaviour 🙂
Kind regards
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### Author:  [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)
#### Post date: [April 26, 2019, 6:16pm UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533/4 "2019-04-26T18:16:34Z")
@non-Jedi, I uploaded my package to Github and then downloaded it from there and now I don’t experience any performance loss. Maybe some other error has occured, which I was not aware of at the time.
Regards
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### Author:  [@rdeits](https://discourse.julialang.org/u/rdeits)
#### Post date: [April 26, 2019, 7:37pm UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533/5 "2019-04-26T19:37:32Z")
It’s hard to say anything without an example. But in general, I would _not_ expect to see any change in performance when a function is moved into a module. If you do find such a case and can reproduce it, then you can certainly post it here: it might indicate a bug in Julia or some other mistake that would be worth correcting.
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### Author:  [@Ahmed\_Salih](https://discourse.julialang.org/u/Ahmed_Salih)
#### Post date: [April 26, 2019, 7:49pm UTC](https://discourse.julialang.org/t/losing-performance-when-adding-function-to-a-package/23533/6 "2019-04-26T19:49:10Z")
If I come across the problem again I will let you guys on discourse now. Currently if any bug would exist it would be due to offline compilation of a package using “activate .” in pkg mode. That is the only difference as far as I can tell from using “add Githublink”
Kind regards