[Haskell-cafe] Speeding up trivial programs

[Viktor Dukhovni]

On Fri, Aug 23, 2024 at 09:22:15PM +0100, Teofil Camarasu wrote:

> On my computer (and using GHC-9.8) it's a bit quicker:
> real    0m0.006s
> user    0m0.001s
> sys     0m0.005s
> 
> I imagine some of this time is just loading things into memory and/or
> running the dynamic linker.
> 
> If you are optimising for start up time, maybe fully statically linking
> your executable might help.

I see similarly low startup using GHC 9.8:

    $ cat hw.hs
    module Main(main) where

    main :: IO ()
    main = putStrLn "Hello World!"

    $ ghc --version
    The Glorious Glasgow Haskell Compilation System, version 9.8.2

    $ ghc -O2 hw.hs
    [1 of 2] Compiling Main             ( hw.hs, hw.o )
    [2 of 2] Linking hw

    $ time ./hw
    Hello World!

    real    0m0.005s
    user    0m0.001s
    sys     0m0.004s

The corresponding C program is not dramatically faster:

    $ cat hw.c
    #include <stdio.h>

    int main(void)
    {
        printf("Hello World!\n");
        return 0;
    }

    $ cc -o hw hw.c

    $ time ./hw
    Hello World!

    real    0m0.002s
    user    0m0.000s
    sys     0m0.002s

So 150ms is fairly anomalous, feels like a site or platform-specific issue,
rather than expected RTS overhead.

-- 
    Viktor.