htmlunit javascript performance - performance

Question

I made a performance test of htmlunit against selenium with firefoxdriver and firefox 21.
The performance test was made on my windows7 machine through Eclipse.
When both have javascript disabled, the performance is the same. When both have javascript turned on htmlunit 2.12 is 150% slower than firefox.
I imagine that this is due the superiority of the spidermonkey engine on rhino.
Is there a way to configure rhino that it will be faster?
Is there anpther way we can speed htmlunit up?
package utils;
import java.io.IOException;
import java.net.MalformedURLException;
import java.text.DateFormat;
import java.util.Date;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;
import org.openqa.selenium.firefox.FirefoxProfile;
import com.gargoylesoftware.htmlunit.BrowserVersion;
import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
import com.gargoylesoftware.htmlunit.WebClient;
import com.gargoylesoftware.htmlunit.html.HtmlPage;
public class PerformanceTest {
public static void main(String[] args) {
String[] urls = new String[] {
...
};
Date beforeSelenium = new Date();
System.out.println("Going to run selenium");
testSelenium(urls);
Date afterSelenium = new Date();
Date beforehtmlUnit= new Date();
System.out.println("Going to run htmlunit");
testHtmlUnit(urls);
Date afterhtmlUnit = new Date();
System.out.println(
DateFormat.getTimeInstance(DateFormat.LONG).format(beforeSelenium));
System.out.println(
DateFormat.getTimeInstance(DateFormat.LONG).format(afterSelenium));
System.out.println(
DateFormat.getTimeInstance(DateFormat.LONG).format(beforehtmlUnit));
System.out.println(
DateFormat.getTimeInstance(DateFormat.LONG).format(afterhtmlUnit));
}
public static void testSelenium(String[] urls) {
WebDriver driver = new FirefoxDriver();
int i=0;
for(String url:urls) {
i++;
System.out.println(i);
// And now use this to visit Google
driver.get(url);
String str = driver.getPageSource();
System.out.println(str);
}
driver.close();
}
public static void testHtmlUnit(String[] urls) {
WebClient client = new WebClient(BrowserVersion.FIREFOX_17);
client.getOptions().setJavaScriptEnabled(true);
client.getOptions().setRedirectEnabled(true);
client.getOptions().setThrowExceptionOnScriptError(false);
client.getOptions().setCssEnabled(true);
client.getOptions().setUseInsecureSSL(true);
client.getOptions().setThrowExceptionOnFailingStatusCode(false);
int i=0;
for(String url:urls) {
i++;
System.out.println(i);
// And now use this to visit Google
HtmlPage page;
try {
page = client.getPage(url);
String str = page.asText();
System.out.println(str);
} catch (FailingHttpStatusCodeException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}

Answer 1

HtmlUnit use a modified, repacked Rhino JavaScript engine. By default is used a interpreter mode. You can enable JavaScript optimization. Then the JavaScript will be compiled to Java byte code.
WebClient webClient = new WebClient();
JavaScriptEngine sriptEngine = webClient.getJavaScriptEngine();
HtmlUnitContextFactory factory = sriptEngine.getContextFactory();
Context context = factory.enterContext();
context.setOptimizationLevel(9);
But this must not speed up your page. It can also slow down it.

Answer 2

The JS engine is the major problem on HtmlUnit performance.
There are some options:
Change Rhino Optimization Settings
Write Rhino Optimized Javascript (hardly it will be enough).
Adapt an external engine (like Chromium).
Wait for Nashorn.
Switch to PhantomJs.