Why does Node.js slow down during iterations? - node.js

Question

I made simple program (code below) it make two loop. First loop makes 5900000000 iteration without any complicated calculation. The second loop counts the time of this first. After 3 to 5 iteration outside loop, the time inner loop take much much larger than earlier (result also below).
I tested it on two environment my local laptop MacBook Pro, and AWS EC2.
Do you have idea why it work that way, and what causing slow down?
const calculate = () => {
let a = 0;
for (let i = 0; i < 5900000000; ++i) {
a++
}
};
for (let i = 0; i < 10; ++i) {
console.time();
calculate();
console.timeEnd();
}
Result:
default: 4.875s
default: 5.566s
default: 29.625s
default: 29.805s
default: 29.698s
default: 29.595s
default: 29.733s
default: 29.611s
default: 29.597s
default: 29.476s
Also, I run app in with profilem mode to saw what happen: NODE_ENV=production node --prof src/index.js
Result:
Statistical profiling result from isolate-0x148040000-5612-v8.log, (81904 ticks, 2 unaccounted, 0 excluded).
[Shared libraries]:
ticks total nonlib name
9 0.0% /usr/lib/system/libsystem_pthread.dylib
5 0.0% /usr/lib/system/libsystem_c.dylib
4 0.0% /usr/lib/libc++.1.dylib
2 0.0% /usr/lib/system/libsystem_malloc.dylib
2 0.0% /usr/lib/system/libsystem_kernel.dylib
[JavaScript]:
ticks total nonlib name
81837 99.9% 99.9% LazyCompile: *calculate /Users/jjuszkiewicz/workspace/nodejs/src/index.js:1:19
[C++]:
ticks total nonlib name
19 0.0% 0.0% T node::contextify::CompiledFnEntry::WeakCallback(v8::WeakCallbackInfo<node::contextify::CompiledFnEntry> const&)
17 0.0% 0.0% T node::builtins::BuiltinLoader::CompileFunction(v8::FunctionCallbackInfo<v8::Value> const&)
5 0.0% 0.0% T _semaphore_destroy
1 0.0% 0.0% t std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long)
1 0.0% 0.0% T _mach_port_allocate
[Summary]:
ticks total nonlib name
81837 99.9% 99.9% JavaScript
43 0.1% 0.1% C++
0 0.0% 0.0% GC
22 0.0% Shared libraries
2 0.0% Unaccounted
[C++ entry points]:
ticks cpp total name
20 52.6% 0.0% T node::contextify::CompiledFnEntry::WeakCallback(v8::WeakCallbackInfo<node::contextify::CompiledFnEntry> const&)
17 44.7% 0.0% T node::builtins::BuiltinLoader::CompileFunction(v8::FunctionCallbackInfo<v8::Value> const&)
1 2.6% 0.0% t std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<char> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long)
[Bottom up (heavy) profile]:
Note: percentage shows a share of a particular caller in the total
amount of its parent calls.
Callers occupying less than 1.0% are not shown.
ticks parent name
81837 99.9% LazyCompile: *calculate /Users/jjuszkiewicz/workspace/nodejs/src/index.js:1:19
81837 100.0% Function: ~<anonymous> /Users/jjuszkiewicz/workspace/nodejs/src/index.js:1:1
81837 100.0% LazyCompile: ~Module._compile node:internal/modules/cjs/loader:1173:37
81837 100.0% LazyCompile: ~Module._extensions..js node:internal/modules/cjs/loader:1227:37
81837 100.0% LazyCompile: ~Module.load node:internal/modules/cjs/loader:1069:33
81837 100.0% LazyCompile: ~Module._load node:internal/modules/cjs/loader:851:24