json decode is slower than go!

[zhuxiujia]

Faster than Java, but seven times slower than golang

Nim Code

import os
import json
import util/benchmark_util

proc getNano() :float64=
    return cpuTime()*1000000000

proc benchmark_item(count_index:int64,count_time:int64,total:float64,callback:proc():void): void =
    echo "bench:",count_index
    let cpuStartTime =  getNano()
    for index in 1..total.toBiggestInt():
         callback()
    var useTime=getNano() - cpuStartTime
    var ns_op=useTime/total
    echo "Time taken: ", useTime,"ns"
    echo ">      number:",total,"      bench: ",ns_op,"  ns/op"

# Statistics execution time
proc benchmark(count_time:int64,total:float64,callback:proc():void) =
    for count_index in 1..count_time:
       benchmark_item(count_index,count_time,total,callback)


type User = object
            id: string
            name: string
            version: int

# echo(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>now  start runing")


proc test(): void =
      let js="""{"id": "","name": "","version": 0}"""
      let jsonNode = parseJson(js)
      let u=to(jsonNode, User)
      #echo u

benchmark(1,3000000,test)
echo "done"

golang Code

type User struct {
	id string
	name string
	version int32
}
func BenchmarkJSON(b *testing.B) {
	b.StopTimer()
	var u=User{
		id:"",
		name:"",
		version:0,
	}
	var v,_=json.Marshal(u)
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		var u=User{}
		 e:=json.Unmarshal(v,&u)
		 if e!=nil{
		 	panic(e)
		 }
	}
}

Current Output

nim output

nim c  -d:release -r main.nim
number:3000000.0      bench: 1568.333333333333  ns/op [Windows: amd64]

go output

nim c  -d:release -r main.nim
number:3000000.0      bench: 205  ns/op   [Windows: amd64]

Expected Output

nim c  -d:release -r main.nim
golang:   number:3000000.0      bench: 205  ns/op   [Windows: amd64]
nim:        number:3000000.0      bench: 1568.333333333333  ns/op   [Windows: amd64]

Possible Solution

JSON standard library optimizes performance

$ nim -v
Nim Compiler Version 1.0.4 [Windows: amd64]

[ghost]

What about using -d:danger instead of -d:release? Also, did you try packedjson (or other nimble JSON decode libs)? And does that JSON performance affect your actual app (not some microbenchmarks)?

[zhuxiujia]

What about using -d:danger instead of -d:release? Also, did you try packedjson (or other nimble JSON decode libs)? And does that JSON performance affect your actual app (not some microbenchmarks)?

use -d:danger it also slow.... my

number:3000000.0 bench: 1390.666666666667 ns/op

and .... My program requires high JSON parsing

Why is compiling to Clang much slower than go？？

[Araq]

Dunno, probably you measure different things.

[zhuxiujia]

Dunno, probably you measure different things.

use packedjson

number:3000000.0 bench: 947.6666666666666 ns/op

and .... Faster than Java, but seven times slower than golang

[Araq]

It's not surprising Go's implementation is faster, they deserialize directly into the struct
which we could also do but don't.

One problem is that Go's implementation is also full of stuff where I can trigger pathological behaviour, you can't just "write a fast JSON library". what if the JSON has a 10GB string literal inside? what if it has object fields with 1000 entries?

JSON is used for everything and so you need to protect against so many different things and then once you did, it's kinda slow for the general case.

Having said that, we'll of course improve the performance further.

[zhuxiujia]

It's not surprising Go's implementation is faster, they deserialize directly into the struct
which we could also do but don't.

One problem is that Go's implementation is also full of stuff where I can trigger pathological behaviour, you can't just "write a fast JSON library". what if the JSON has a 10GB string literal inside? what if it has object fields with 1000 entries?

JSON is used for everything and so you need to protect against so many different things and then once you did, it's kinda slow for the general case.

Having said that, we'll of course improve the performance further.

If it's fast, it's a great programming language

[disruptek]

Jason doesn't deserialize (yet).

[FedericoCeratto]

Related to #3809 and #12152