v8.serialize is so strange!

[askforone]

• **Node.js Version 8.94:
• OS: Win7 64

I think v8.serialize will be faster than JSON... but not?
and
v8.serialize(value) is slower than v8.serialize(value).toString()

Plz test the codes below;

// I am an example of JS code
var deco_getSyncRunTime = function(func, times){
    var t = Date.now();
    for(var i=0; i<times; i++){
        func();
    }
    console.log('run time:', Date.now() - t);
    console.log(process.memoryUsage());
}

var v8 = require('v8');
var test_func_1 = function(){
    return v8.serialize(obj).toString(); //1e6   11sec
}
var test_func_2 = function(){
    return v8.serialize(obj);  //1e6   21sec    why
}
var obj = {"dirty_map":{"pid":1},"pid":1,"uid":"","wid":"","phone":"","wechat":"","currency_1":3000,"char_1":{"dirty_map":{"money":1},"money":5}};

setTimeout(function(){
    deco_getSyncRunTime(test_func_1, 1e6);
    //deco_getSyncRunTime(test_func_2, 1e6);
}, 1e4);

-->

[bnoordhuis]

I think v8.serialize will be faster than JSON... but not?

Its raison d'être is that it supports more types than plain JSON. No one said anything about it being faster. :-)

[askforone]

but why
v8.serialize(obj).toString() is faster than v8.serialize(obj)

[bnoordhuis]

I ran it a few times and there's so much variance between runs that I can't really draw meaningful conclusions but it's probably because the .toString() forces more GC scavenges, keeping the memory footprint down.

If you start node with --expose_gc and call gc() every 1,000 iterations, they perform about the same.

[askforone]

I think it's not a reasonable explanation, gc may cost more time。
so I feel there's something wrong of the buffer gc。does buffer still alloc external memory outside of v8?

[bnoordhuis]

Yes.

[gireeshpunathil]

close-able?

[gireeshpunathil]

closing as answered, please re-open if it is still outstanding.