# Regression in Precompile time with 1.10.0-rc2 compared to the rc1 version

**URL:** <https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324>\
**Category:** Internals & Design\
**Tags:** question\
**Created:** [December 8, 2023, 12:23pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324 "2023-12-08T12:23:05Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![svretina](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/svretina/32/206157_2.png) [@svretina](https://discourse.julialang.org/u/svretina)\
**Post date:** [December 8, 2023, 12:23pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/1 "2023-12-08T12:23:05Z")

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I recently upgraded to the 1.10.0-rc2 version and I see a regression in the precompilation time of my package. There is no option in `juliaup` to revert back to rc1. Do you also see this with the rc2 version?

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**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [December 8, 2023, 12:28pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/2 "2023-12-08T12:28:31Z")

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> [@svretina](#):
>
> There is no option in `juliaup` to revert back to rc1.

```julia
juliaup add 1.10.0-rc1

```

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**Author:** ![svretina](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/svretina/32/206157_2.png) [@svretina](https://discourse.julialang.org/u/svretina)\
**Post date:** [December 8, 2023, 12:31pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/3 "2023-12-08T12:31:11Z")

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ah, thanks. It wasn’t showing up in the  
`juliaup list`. But is the regression with compile time something that you also see or is it just me?

As I understood, in the rc1 version once a package is precompiled, the next time you load it, its instant. This behavior is not present with the rc2 version. Each time I load the package it precompiles dependencies.

On top of that I see an increase in precompilation time around ~20%.

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**Author:** ![ufechner7](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ufechner7/32/51363_2.png) [@ufechner7](https://discourse.julialang.org/u/ufechner7)\
**Post date:** [December 8, 2023, 1:21pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/4 "2023-12-08T13:21:00Z")

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> [@svretina](#):
>
> Each time I load the package it precompiles dependencies.

There is something wrong then. Are you using local environments? What is the output of

```julia
using Pkg; Pkg.status()

```

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<div class="post-metadata">

**Author:** ![giordano](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/giordano/32/2166_2.png) [@giordano](https://discourse.julialang.org/u/giordano)\
**Post date:** [December 8, 2023, 2:04pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/5 "2023-12-08T14:04:34Z")

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> [@svretina](#):
>
> It wasn’t showing up in the  
> `juliaup list`.

Interesting:

```console
% juliaup list | grep '1\.10\.0-rc1'
 1.10.0-rc1 1.10.0-rc1+0.x64.linux.gnu      
 1.10.0-rc1~x64 1.10.0-rc1+0.x64.linux.gnu      
 1.10.0-rc1~x86 1.10.0-rc1+0.x86.linux.gnu 

```

> [@svretina](#):
>
> But is the regression with compile time something that you also see or is it just me?

I don’t know, I haven’t tried it. But if you can quantify the regression (0.1%? 1%? 10%? 100%?) and have a reproducer it may be useful to open an issue about it.

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**Author:** ![ianshmean](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ianshmean/32/216042_2.png) [@ianshmean](https://discourse.julialang.org/u/ianshmean)\
**Post date:** [December 8, 2023, 3:13pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/6 "2023-12-08T15:13:33Z")

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> As I understood, in the rc1 version once a package is precompiled, the next time you load it, its instant. This behavior is not present with the rc2 version. Each time I load the package it precompiles dependencies.

@svretina can you retry with `ENV["JULIA_DEBUG"]="loading"` and show the output you see when you hit repeat precompilation

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<div class="post-metadata">

**Author:** ![svretina](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/svretina/32/206157_2.png) [@svretina](https://discourse.julialang.org/u/svretina)\
**Post date:** [December 11, 2023, 4:31pm UTC](https://discourse.julialang.org/t/regression-in-precompile-time-with-1-10-0-rc2-compared-to-the-rc1-version/107324/7 "2023-12-11T16:31:25Z")

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Hi,  
I am trying to time the precompilation time for each version. In order to force precompilation, do I need to remove the contents of the cached libraries?.

Both of the versions load the cached libraries, according to the `ENV["JULIA_DEBUG"]="loading"` suggestion from @ianshmean .