Is there a way to set cargo to default add -j 4 to all the calls?
As workaround I've used this script:
cargoj4
#!/bin/bash
cargo "$1" -j 4
but this does not always work (I forget to call it :-\ or I have scripts in the project that use cargo and I cannot modify them).
You can create a config.toml to define parallel jobs. You need to create .cargo/config.toml. You can define it globally or per project, depending on your needs.
And then you just need to add
[build]
jobs = 4 # number of parallel jobs, defaults to # of CPUs
You also have the possiblity of creating an alias for your command, which you would put in the same file:
[alias]
j4 = "build -j 4"
And then you can just invoke it as cargo j4
You can set this in cargo configuration file. You can create a config file in $HOME/.cargo/config.toml with the configuration you need.
[build]
jobs = 4 # number of parallel jobs, defaults to # of CPUs
Read more about Hierarchical structure, Configuration format and Jobs option here.