The startup time of a programming language is important for short running programs that are called interactively by the user or are called (many times) by other programs. For example, the version control system Git is written in C and the invoked commands (like git status and git log) execute fast. The version control systems Bazaar and Mercurial are written in Python. They take much longer to execute than Git and they feel slow compared to Git. The startup time of Python contributes an important portion of the execution time.

Several years ago, I wrote a small script named distro-info which provides information about the Debian/Ubuntu releases. This script is called in a bash completion for pbuilder-dist (from the ubuntu-dev-tools package). An Ubuntu user experience a bash startup of 4 seconds with cold cache due to the multiple invocations of distro-info. This made me search a suitable programming language with a fast startup time and I wrote this man page to measure the startup time of many programming languages.

This project consists of many hello world programs in different languages and an ugly Makefile that compiles the programs and runs the benchmark. Each program is run 1000 times in a row (using a tiny run.c program to minimize the overhead for the invocation):

time -f "%e" taskset -c 0 ./run 1000 $program

Before running the benchmark, install all relevant compilers. On Debian/Ubuntu you can run make install to install the compilers. Then start the benchmark by calling make:

$ make
Run on: Intel(R) Core(TM) i5-2400S CPU @ 2.50GHz | Ubuntu 17.10 | 2018-02-10
C (gcc 7.2.0):            0.26 ms
C++ (g++ 7.2.0):          0.79 ms
Cython (cython 0.25.2):   9.91 ms
Cython3 (cython3 0.25.2): 26.04 ms
D (gdc 7.2.0):            0.57 ms
Go (go go1.8.3):          0.41 ms
Go_GCC (gccgo 7.2.0):     98.26 ms
Haskell (ghc 8.0.2):      0.72 ms
Pascal (fpc 3.0.2):       0.08 ms
Rust (rustc 1.21.0):      0.51 ms
Bash 4.4.12(1):           0.71 ms
CShell 20110502:          3.26 ms
Lua 5.2.4:                0.63 ms
Perl 5.26.0:              0.94 ms
PHP 7.1.11:               8.71 ms
Python-S 2.7.14:          2.91 ms
Python 2.7.14:            9.43 ms
Python3-S 3.6.3:          9.31 ms
Python3 3.6.3:            25.84 ms
PyPy 5.8.0:               27.53 ms
Ruby 2.3.3p222:           32.43 ms
Shell (dash 0.5.8):       0.33 ms
ZShell 5.2:               1.57 ms
C# (mcs 4.6.2.0):         13.37 ms
Java (javac 1.8.0_151):   54.55 ms
Scala (scalac 2.11.8):    310.81 ms

$ make
Run on: Raspberry Pi 3 (arm64) | Debian GNU/Linux buster/sid | 2018-02-10
C (gcc 7.2.0):            2.19 ms
C++ (g++ 7.2.0):          8.24 ms
Cython (cython 0.26.1):   98.71 ms
Cython3 (cython3 0.26.1): 196.36 ms
Go (go go1.9.3):          4.10 ms
Go_GCC (gccgo 7.2.0):     898.30 ms
Haskell (ghc 8.0.2):      9.44 ms
Pascal (fpc 3.0.4):       0.66 ms
Rust (rustc 1.22.1):      4.42 ms
Bash 4.4.12(1):           7.31 ms
CShell 20110502:          10.98 ms
Lua 5.2.4:                6.23 ms
Perl 5.26.1:              8.78 ms
PHP 7.2.2:                98.03 ms
Python-S 2.7.14+:         32.77 ms
Python 2.7.14+:           91.85 ms
Python3-S 3.6.4:          110.02 ms
Python3 3.6.4:            197.79 ms
PyPy 5.8.0:               183.50 ms
Ruby 2.3.6p384:           421.53 ms
Shell (dash 0.5.8):       2.81 ms
ZShell 5.4.2:             11.04 ms
C# (mcs 4.6.2.0):         137.53 ms
Java (javac 1.8.0_151):   566.66 ms
Scala (scalac 2.11.8):    2989.72 ms

If you don't want to test all programming languages, edit COMPILED_LANGS and INTERPRETED_LANGS in Makefile (and maybe edit the all target to not depend on the .exe and .class files). Note: The Makefile should be replaced by something else that is simpler to read and can produce nicer looking output.

I categorize the programming languages in four categories: fast, okay, slow, takes ages.

Fast startup times are below 1 ms on my desktop (Intel Core i5 2400S) and below 10 ms on slow hardware (Raspberry Pi 3):

• Bash
• C
• C++
• D (gdc)
• Go (go)
• Haskell
• Lua
• Pascal
• Perl
• Rust
• Shell (dash)

Okayish startup times are between 1 and 5 ms on my desktop (Intel Core i5 2400S) and between 10 and 50 ms on slow hardware (Raspberry Pi 3):

• CShell
• Python 2 (with -S)
• ZShell

Slow startup times are between 5 and 50 ms on my desktop (Intel Core i5 2400S) and between 50 and 500 ms on slow hardware (Raspberry Pi 3):

• C# (mcs)
• Cython (Python 2)
• Cython3 (Python 3)
• PHP
• Python 2
• Python 3
• Python 3 (with -S)
• PyPy (Python 2)
• Ruby

Some programming languages take ages to start up. The startup times are above 50 ms on my desktop (Intel Core i5 2400S) and over 500 ms on slow hardware (Raspberry Pi 3):

• Java
• Go (gccgo)
• Scala