Okay, here’s an example.
We’ll use this program, which is a mandelbrot benchmark: crystal-benchmarks-game/mandelbrot.cr at master · kostya/crystal-benchmarks-game · GitHub (run it with 10000)
- Without --release
- Time to compile: 1.35s
- Time to execute: 15s
- With the old --release mode
- Time to compile: 7.75s
- Time to execute: 7.32s
- With the new --release mode
- Time to compile: 3.14s
- Time to execute: 8.53s
You can already see that the new --release mode is closer to “without --release” when it comes to how long it takes to compile the program, and closer to “with the old --release” when it comes to executing the program
Next, havlak: crystal/havlak.cr at master · crystal-lang/crystal · GitHub
- Without --release
- Time to compile: 1.5s
- Time to execute: 35.56s
- With the old --release mode
- Time to compile: 8.71s
- Time to execute: 9.42s
- With the new --release mode
- Time to compile: 3.27s
- Time to execute: 15.29s
Actually, it seems that this new --release mode is right in between the two modes. So these could be similar to -O1, -O2 and -O3 from other build systems… maybe?
Finally, let’s take a big program: the compiler.
Compiling the compiler in release mode goes from about 5 minutes to 1.5 minutes. Then, compiling that havlak program above in non-release mode goes from 1.72s to 2.24s. To compile the compiler in non-release mode again, it goes from 33.35s to 38.98s.
(this last part was a bit confusing, but it shows that with this new approach, we’ll have to wait 1.5 minutes to compile the compiler in release mode instead of 5 minutes, but then compiling the compiler with this new compiler takes 38.98s instead of 33.35s, because it’s slightly slower)