Linux performance issues

[ghost]

Hi,

We talked about the GC features not yet implemented on Linux. Following is an example of where JsCreateString in a hot path can severely harm perfomance:

#include <ChakraCore.h>
#include <iostream>
#include <cstring>
#include <fstream>

void registerGlobalFunction(const char *name, JsNativeFunction nativeFunction) {
    JsValueRef jsFunction;
    JsCreateFunction(nativeFunction, nullptr, &jsFunction);
    JsPropertyIdRef propertyId;
    JsCreatePropertyIdUtf8(name, strlen(name), &propertyId);
    JsValueRef globalObject;
    JsGetGlobalObject(&globalObject);
    JsSetProperty(globalObject, propertyId, jsFunction, true);
}

JsContextRef context = 0;
JsValueRef cbFunction = 0;

int main(int argc, char **argv) {

    std::string script = "setCb((verb) => {});";

    JsRuntimeHandle runtime = 0;
    JsValueRef result = 0;
    unsigned currentSourceContext = 0;

    JsCreateRuntime(JsRuntimeAttributeEnableExperimentalFeatures, nullptr, &runtime);
    JsCreateContext(runtime, &context);
    JsSetCurrentContext(context);

    registerGlobalFunction("setCb", [](JsValueRef callee, bool isConstructCall, JsValueRef *arguments,
                           unsigned short argumentCount, void *data) -> JsValueRef {
        JsAddRef((cbFunction = arguments[1]), nullptr);
        return nullptr;
    });

    JsValueRef scriptSource = 0, scriptUrl = 0;
    JsCreateExternalArrayBuffer((void *) script.data(), script.length(), nullptr, nullptr, &scriptSource);

    JsCreateString("scriptUrl", 4, &scriptUrl);
    JsRun(scriptSource, currentSourceContext++, scriptUrl, JsParseScriptAttributeNone, &result);

    JsValueRef globalObject = 0;
    JsGetGlobalObject(&globalObject);

    const char string[] = "Something for JS-land";

    // adjust this number for your computer
    for (int i = 0; i < 20000; i++) {
        JsValueRef verb = 0;
        // creation of this string cause major slowdown
        JsCreateString(string, sizeof(string) - 1, &verb);

        JsValueRef arguments[] = {globalObject, verb};
        JsCallFunction(cbFunction, arguments, 2, &result);
    }

    JsSetCurrentContext(JS_INVALID_REFERENCE);
    JsDisposeRuntime(runtime);

    std::cout << "Reached the end" << std::endl;
    return 0;
}

[obastemur]

I was suspecting from Utf8 encode/decode stuff at first. However, testing the sample above with different inputs show GC is the real cause. (note: we don't have high performance GC features available on xplat yet.)

20K -> original loop

real	0m0.339s
user	0m0.324s
sys	0m0.008s

30K

real	0m0.902s
user	0m0.786s
sys	0m0.018s

50K

real	0m1.718s
user	0m1.702s
sys	0m0.009s

@alexhultman Thanks for the test case.

[digitalinfinity]

@leirocks @jianchun FYI, worth running this test case as part of SWB/Partial GC validation

[obastemur]

This is no longer an issue. @alexhultman could you please contribute this sample as a test case?

Create a new folder under test/native-tests and copy Platform.js and sample.cpp from test-char. Update the sample.cpp with your code above. JsCreatePropertyIdUtf8 -> JsCreatePropertyId