# Minimising top-level project latency
**URL:** https://discourse.julialang.org/t/minimising-top-level-project-latency/80546
**Category:** Performance
**Created:** [May 5, 2022, 2:25pm UTC](https://discourse.julialang.org/t/minimising-top-level-project-latency/80546 "2022-05-05T14:25:30Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@danielsoutar](https://discourse.julialang.org/u/danielsoutar)
#### Post date: [May 5, 2022, 2:25pm UTC](https://discourse.julialang.org/t/minimising-top-level-project-latency/80546/1 "2022-05-05T14:25:30Z")
If I want to use a third-party package with minimal latency overhead, I can do so by having it precompiled. However, I am in the top-level project in a codebase that implements a complex pipeline and get this error when `instantiate`ing:
```julia
(MyPackage) pkg> instantiate
Precompiling project...
Progress [========================================>] 1/1
✗ MyPackage
0 dependencies successfully precompiled in 3 seconds (102 already precompiled)
1 dependency errored
```
Is there any way I can debug this error? Bear in mind this project is user-facing, so I am not sure if it can be precompiled, or if only some parts can be precompiled.
---
### Author:  [@Salmon](https://discourse.julialang.org/u/Salmon)
#### Post date: [May 5, 2022, 2:37pm UTC](https://discourse.julialang.org/t/minimising-top-level-project-latency/80546/2 "2022-05-05T14:37:24Z")
AFAIK you should get an actual error message if you call
```julia
] precompile
```
explicitly.
To be safe, I would try it in a fresh REPL.
If the error you get does not occur in your code but in some dependency, try updating your environment. In the worst case you might have to wait for an update of your dependencies I think.
Generally speaking, precompilation should work. Even less overhead is achieved by using PackageCompiler.jl, but you should only attempt this if your package precompiled successfully and you don’t have to make any more changes to it.
---
### Author:  [@danielsoutar](https://discourse.julialang.org/u/danielsoutar)
#### Post date: [May 5, 2022, 4:28pm UTC](https://discourse.julialang.org/t/minimising-top-level-project-latency/80546/3 "2022-05-05T16:28:34Z")
So the command the package uses is this:
`julia --project src/MyPackage.jl some-arg-goes-here`
And that file looks like this:
```julia
using Compat
# Verify if installed Julia version is in range of required Julia versions
minver = VersionNumber("1.6.0")
if VERSION < minver
@error "Your Julia version is $(VERSION) while MyPackage requires Julia version to be a minimum $(minver)"
exit(1)
end
include("AllModules.jl") # I am not defending this design choice
import .AllModules
AllModules.Pipeline.run(Base.ARGS)
```
The issue is that when I try to use `precompile` I get this error trace, and I definitely don’t understand this. Happens with or without `using Compat` above:
```julia
(MyPackage) pkg> precompile
ERROR: LoadError: UndefVarError: include not defined
Stacktrace:
[1] top-level scope
@ ~/Develop/mypackage/src/MyPackage.jl:10
[2] include
@ ./Base.jl:386 [inlined]
[3] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt64}}, source::Nothing)
@ Base ./loading.jl:1213
[4] top-level scope
@ none:1
[5] eval
@ ./boot.jl:360 [inlined]
[6] eval(x::Expr)
@ Base.MainInclude ./client.jl:446
[7] top-level scope
@ none:1
```
Not sure if it has something to do with [this issue?](https://github.com/JuliaLang/PackageCompiler.jl/issues/216)
---
### Author:  [@Salmon](https://discourse.julialang.org/u/Salmon)
#### Post date: [May 5, 2022, 5:25pm UTC](https://discourse.julialang.org/t/minimising-top-level-project-latency/80546/4 "2022-05-05T17:25:03Z")
> [@danielsoutar](#):
>
> So the command the package uses is this:
>
> `julia --project src/MyPackage.jl some-arg-goes-here`
What is the reason why you select `src/MyPackage.jl` as the directory of your environment? Personally, I tend to activate environments in the REPL, but as I understand it, you should put the directory of the `Project.toml` file here (usually in the parent directory of `src/`. This is probably not your issue though.
> [@danielsoutar](#):
>
> The issue is that when I try to use `precompile` I get this error trace, and I definitely don’t understand this. Happens with or without `using Compat` above:
>
> ```julia
> (MyPackage) pkg> precompile
> ERROR: LoadError: UndefVarError: include not defined
> Stacktrace:
> [1] top-level scope
> @ ~/Develop/mypackage/src/MyPackage.jl:10
> [2] include
> @ ./Base.jl:386 [inlined]
> [3] include_package_for_output(pkg::Base.PkgId, input::String, depot_path::Vector{String}, dl_load_path::Vector{String}, load_path::Vector{String}, concrete_deps::Vector{Pair{Base.PkgId, UInt64}}, source::Nothing)
> @ Base ./loading.jl:1213
> [4] top-level scope
> @ none:1
> [5] eval
> @ ./boot.jl:360 [inlined]
> [6] eval(x::Expr)
> @ Base.MainInclude ./client.jl:446
> [7] top-level scope
> @ none:1
>
> ```
>
> Not sure if it has something to do with [this issue?](https://github.com/JuliaLang/PackageCompiler.jl/issues/216)
The issue points to the `PackageCompiler` package, I assume you are not using this, correct?
Which of these things are you trying to do?
1. Create a package, which is then precompiled upon its first use?
2. Or use PackageCompiler.jl to compile a script. The script will be run and the fully compiled functions are saved to a file which can be used to start later sessions.
If the answer is 1.:
Possibly the reason why you cannot precompile is that your package is not defined as a module? Usually, a Julia package looks like this:
```julia
module MyPackage
using Compat
# Verify if installed Julia version is in range of required Julia versions
minver = VersionNumber("1.6.0")
if VERSION < minver
@error "Your Julia version is $(VERSION) while MyPackage requires Julia version to be a minimum $(minver)"
exit(1)
end
include("AllModules.jl") # I am not defending this design choice
import .AllModules
AllModules.Pipeline.run(Base.ARGS)
end #Module
```
Does the error go away if you define your package this way and include it with
```julia
]activate MyPackage
using MyPackage
```
If the answer is 2. Try first to run your script with
```julia
julia src/MyPackage.jl
```
if this runs without errors, you can try to follow the steps given in
> **[Creating a sysimage for fast plotting with Plots.jl · PackageCompiler](https://julialang.github.io/PackageCompiler.jl/stable/examples/plots.html)**
>
> Documentation for PackageCompiler.
to create a sysimage.
Hope this helps