Weird interaction between packages

General Usage
1

I am trying to reduce the load time of my project. What I found, using:

using Timers; tic()

using MAT, PyPlot

function read_lookup(varname="Tables")
    file = matopen(joinpath("data", "TablesCpCtCq.mat"))
    res  = read(file, varname)
    close(file)
    res
end

start=toc()
tables=read_lookup()
stop=toc()
println(stop-start)

# Startup:           0.8s
# read_lookup:       1.2s

# without PyPlot
# Startup:           0.0s
# read_lookup:       0.4s

I am just looking at the initial compilation time and I am using a custom system image.

If I do not load PyPlot, the first call to read_lookup needs 0.4s, if I have using PyPlot in the code the same call needs 1.2s.

Any idea?

2

It’s probably method invalidation:

See the following if you want to analyze further:
https://timholy.github.io/SnoopCompile.jl/dev/snoopr/

3

Better example, includes a function to create the test file:

using Timers; tic()

using MAT#, PyPlot

function read_lookup(varname="varname")
    file = matopen("matfile.mat")
    res  = read(file, varname)
    close(file)
    res
end

function create_mat_file()
    variable=zeros(40,40)
    file = matopen("matfile.mat", "w")
    write(file, "varname", variable)
    close(file)
end

start=toc()
tables=read_lookup()
stop=toc()
println(stop-start)

# Startup:        0.83s
# load_mat:       0.73s

# without PyPlot
# Startup:        0.0s
# load_mat:       0.4s