Compare startup time Node.JS, Python, GO

Node.JS and Python are interpreted scripting languages. So they have to start the interpreter, compile the Source code and the execute.

In go you have the choice.

  1. Compile and run: `go run main.go``
  2. Compile, then run:
    • go build main.go
    • ./main

So GO programs can be much faster. The problem with measuring the execution time is that you would need a single tasked computer with no other processes running. And there are changes etc… But to get an idea, we use the “time” command (available on MAC and linux).

You should at least call the time two times, several calls give you an better idea but also subsequent calls will be optimized by you operation system, for example the files used will be in read buffers.

Understanding output of time

You can measure any command with time. It will give you these outputs:

  • User time
  • System time
  • Real time

Real time is the actual elapsed time from start to finish. Less is better, but if your CPU is busy doing other things, this number will be higher and is has nothing to do with the program measured.

User time is the portion of CPU time spent within the process in user mode code (outside the kernel). Less is better.

System is the portion of CPU time spent in the kernel within the process. Calling i/o and stuff. Less is better.

On some OS/shell you will get %CPU in addition: % CPU is the percent of cpu time used. Less is better


The Code

package main

import "fmt"

func main() {
echo "Node.JS"
time node index.js
time node index.js
echo  "Python"
time python3
time python3
echo "Go run"
time go run main.go
echo "Build Go"
go build -o hello main.go
echo "Execute static binary"
time ./hello  
time ./hello  

To keep it simple I just did two iterations. To have an environment without virus scan etc i used an environment



real    0m0.040s
user    0m0.041s
sys     0m0.001s

real    0m0.038s
user    0m0.035s
sys     0m0.005s

Node.JS takes about 0.04 seconds.



real    0m0.085s
user    0m0.054s
sys     0m0.038s

real    0m0.084s
user    0m0.050s
sys     0m0.040s

Python takes about 0.08 seconds

GO as script

Go run

real    0m0.470s
user    0m0.213s
sys     0m0.313s

Oh no, go is slow - but this is compilation and execution.

Now we change gears…

Compiled GO

Build Go
Execute static binary

real    0m0.002s
user    0m0.003s
sys     0m0.000s

real    0m0.002s
user    0m0.000s
sys     0m0.003s

Go takes 0.002 which multiple times faster than python and Node.JS.


See the full source on github.