Google Web Toolkit

Speed Tracer FAQ

On this page you will find answers to some Frequently Asked Questions about Speed Tracer.

  1. Installation
    1. Why do I get the error, 'Invalid value for 'permissions[0]'?
    2. Why am I still getting the warning "No data received in 6 seconds. Chrome must be run with the flag..."?
    3. I added the --enable-extension-timeline-api flag and now Chrome won't start.
  2. Running Speed Tracer
    1. Why can't I use the Chrome Devtools Inspector when Speed Tracer is up?
    2. I can't open a Speed Tracer dump saved to the local filesystem.
    3. I can't profile my GWT applications using the Google Plugin for Eclipse.
    4. Why do I see 404 errors when using Speed Tracer to monitor my app?
  3. Contributing
    1. Is Speed Tracer Open Source?

Installation

Why do I get the error, 'Invalid value for 'permissions[0]'?

First, check to be sure that you are running a version of Chrome that is compatible with Speed Tracer (4.0.249.30 or later should work for Windows and Linux). You can check the version number under the About menu item.

Also make sure you are not trying to install the extension in incognito mode.

Why am I still getting the warning "No data received in 6 seconds. Chrome must be run with the flag..."? I already added the --enable-extension-timeline-api flag.

First, you must be sure your version of Google Chrome is recent enough (version 4.0.249.30 or later should work)

Close all instances of Google Chrome before running the shortcut you created. If you are using Microsoft Windows, check your task manager to be sure you dont have a zombie chrome.exe process hanging around. If even one Google Chrome process is still up, it will fork a Google Chrome window from the existing instance of the browser and the new command line option will be ignored.

I added the --enable-extension-timeline-api flag and now Google Chrome won't start.

On Microsoft Windows, if there is a problem in the target field of the shortcut properties, you will get an error dialog with the title "Problem with Shortcut." If the path to Google Chrome is enclosed in double quotes, make sure that the --enable-extension-timeline-api flag is outside the quotes similar to the following example:

  "C:\Documents and Settings\Default\Local Settings\Application Data\Google\Chrome\Application\chrome.exe" --enable-extension-timeline-api

Running Speed Tracer

Why can't I use the Chrome Devtools Inspector when Speed Tracer is up?

This is a side effect of how we reach in to collect our instrumentation. We are working to fix this, but for now, all you have to do is close the Speed Tracer window, and you can then Inspect the target page just like you did before.

I can't open a Speed Tracer dump saved to the local filesystem.

Changes to the Chrome extension security model require you to authorize extensions to access the local filesystem. If you are using a file:/// URL to access a speedtracer dump, you may not be able to access it until you perform the following action:

  1. Open the Chrome wrench menu
  2. Select the Tools menu item
  3. Select the Extensions menu item
  4. Under the Speed Tracer extension entry, check the checkbox for Allow access to file URLs

After performing this action, try reloading the page with your dump file and a button to launch the Speed Tracer monitor window should appear.

I can't profile my GWT applications using the Google Plugin for Eclipse.

The Chrome extension security model may be blocking requests made to the local filesystem. Enable access to file:/// URLs as described above.

Why do I see 404 errors when using Speed Tracer to monitor my app?

Speed Tracer makes some extra network requests for symbol manifests to support resymbolization of stack traces. If you don't have a server running to serve symbol manifests, such as the Google Plugin for Eclipse, these requests will fail. There shouldn't be any other observable impact on your application.

Contributing

Is Speed Tracer Open Source?

Yes. You can find out more on the Speed Tracer project on Google Code.

Except as otherwise noted, the content of this page is licensed under the Creative Commons Attribution 3.0 License.

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