slow JS / C++ bridge

[farfromrefug]

I decided run some tests comparing perfs of the actual runtime vs v8 runtime.
One thing which worries me quite a bit is the "bridge time".
I have made a test to run this function on an array of 100000 points.
On the current runtime it takes around 60ms. With the v8 runtime it takes around 300ms.
That means a 5x slower runtime in a sense :s
The test was made on simulator.

Dont know if anything can be done about this. Would love to get your view on this

[farfromrefug]

Jut to add on this why it worries me. One already existing case where you get fast native calls is requestAnimationFrame which makes calls to __tns_uptime at a high framerate.

[darind]

Thanks for the observation. We will look into this and report back any findings.

[darind]

@farfromrefug, could you please provide a sample illustrating the slowdown?

I have tried the following method:

class Path {
    constructor() {
        this.path_ = CGPathCreateMutable();
        CGPathMoveToPoint(this.path_, null, 0, 0);
    }

    lineTo(x, y) {
        CGPathAddLineToPoint(this.path_, null, x, y);
    }
}

let count = 400;
let point = new Path();
console.time("perf");

for (var x = 0; x < count; x++) {
    for (var y = 0; y < count; y++) {
        point.lineTo(x, y);
    }
}

console.timeEnd("perf");

and it produced similar results with both runtimes.

[farfromrefug]

@darind can you try with 10000 points?
With not many points it was small enough to not be seen

[farfromrefug]

@darind sorry misread your example. It was actually 400 * 400 calls ...
Just ran it again with your latest:

• ios-runtime : 87ms
• ios-v8-runtime: 400ms

[darind]

@farfromrefug, we have released several fixes that should improve the performance of method calls. Running this test in release mode on an iPhone X (iOS 13.2.2) yields the following results:

• ios-runtime: 80ms
• ios-v8-runtime: 91ms

The new runtime is still a bit slower but we are getting closer and the difference is quite insignificant.

Can you verify if you are observing improved performance with your tests?

[farfromrefug]

@darind really awesome! Amazing work as always! Will test that tomorrow

[darind]

@farfromrefug, we have released some additional perf improvements that have closed the gap between the beta and the official runtime.

[farfromrefug]

@darind with 6.5.0-beta.2-v8-2020-01-29-122856-01 :
*ios-v8-runtime: 157.827ms
*ios-runtime: 80.945ms

Seems to be the best i can get

[darind]

@farfromrefug, on what device are you running the test? I am getting identical results for both runtimes on an iPhone X (app built in release mode).