Swifts build system can split off enough threads to consume all of your CPU cores, and batch mode did improve things, but it's not actually doing so efficiently. There is a trade off between total compute time used and number of threads used. In compute time consumed, swift is the most efficient when it's single threaded in WMO mode, but this means you can only compile in parallel with separate modules that don't depend on each other. And even then it's not a very fast compiling language itself, multithreading issues notwithstanding
Maybe something has changed recently, but as far as Xcode 12 goes, I haven't noticed much of a difference. I last checked deeply with swift 4.
Swifts build system can split off enough threads to consume all of your CPU cores, and batch mode did improve things, but it's not actually doing so efficiently. There is a trade off between total compute time used and number of threads used. In compute time consumed, swift is the most efficient when it's single threaded in WMO mode, but this means you can only compile in parallel with separate modules that don't depend on each other. And even then it's not a very fast compiling language itself, multithreading issues notwithstanding
Maybe something has changed recently, but as far as Xcode 12 goes, I haven't noticed much of a difference. I last checked deeply with swift 4.
More details here: https://github.com/apple/swift/blob/master/docs/CompilerPerf...