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Ask HN: Why does Node.js start so slow?

2 points by FreeHugs ↗ HN
time php -r 'echo 123;'

outputs:

    123
    real 0m0.031s
    user 0m0.023s
    sys 0m0.008s
time python3 -c 'print (123)'

outputs:

    123
    
    real 0m0.022s
    user 0m0.019s
    sys 0m0.004s
time node -e 'console.log(123);'

outputs:

    123

    real 0m0.578s
    user 0m0.551s
    sys 0m0.028s
Why is the node version more than 10 times slower than the PHP and Python versions?

6 comments

[ 3.1 ms ] story [ 27.0 ms ] thread
efortis
What's your output for: `which node` and `node -v`

On my M1 Pro:

    python3 -c 'print (123)'    0.02s user 0.01s system 86% cpu 0.036 total
    node -e 'console.log(123)'  0.04s user 0.01s system 88% cpu 0.053 total
FreeHugs
which node: /usr/bin/node

node -v: v10.24.0

And for you?

When I install it from https://deb.nodesource.com/setup_16.x then I get:

node -v: v16.15.0

And indeed, then the time goes down by a factor of 10:

time node -e 'console.log(123);'

Now outputs:

    123
    
    real 0m0.058s
    user 0m0.046s
    sys 0m0.013s
JohnHaugeland
You're measuring how slowly your computer follows symlinks
FreeHugs
Can you elaborate?
JohnHaugeland
Take your original setup. Run it. Time it.

Now, using `which`, invoke it directly, instead of through the symlink. Time it again.

raxxorraxor
I guess the reason is that the runtime of node is so much larger than that of Python and PHP. I think the Node runtime is already at > 50MB as a binary.

I don't know how large Python and PHP runtimes are, but I know python is often stripped down to a few kilobytes for embedded systems.

I guess if you preload the runtimes before executing these commands, the execution should be fairly similar for each one (near zero, more depending on I/O).