ADVISOR DETAILS

RECENT BLOG POSTS

Self-test: Collecting basic performance data with GPA

So you want to self-test your game, and collect some basic performance data. You’re going to use Intel GPA to analyze your game on Windows, but you’re not quite sure how to get started. Here are some simple steps to get you running quickly.

Getting started

You’ll be collecting some real-time data as you play your game (watching and then capturing it with the GPA System Analyzer), and you’ll then capture one or more game frames to study more deepy with GPA Frame Analyzer. This will give you data files you can analyze, or to share with somebody else if you wish to review your performance with them.

Pick some part of your game that represents typical gameplay. Be ready to play it while you capture data. If you have very different parts of gameplay, plan to study each. You’ll want to profile every aspect of your game (loading screens, menus, etc.) but the single most important part is typical gameplay, so start there.

There are a few problem cases to sort out first. At the moment, you won’t be able to use GPA if:

  • This is an OpenGL game – GPA doesn’t support OpenGL on Windows. Are you an OpenGL developer? Head to the GPA Forum and let us know what you think.
  • You’re running DX 10.x on Windows 8. Switch to DX11 if you can, otherwise you’ll need to collect data on Windows 7.
  • More details on what works and doesn’t are listed in the GPA release notes.

Install

Install GPA on your test system (sometimes called the test target), and also on another system (the analysis platform). You may find it convenient to have the install set up desktop icons for you. The configuration of the analysis system doesn’t matter much, but it needs to be running Windows 7 or Windows 8.

Launch and connect

Start the GPA Monitor on both systems. You’ll see it in the taskbar.

On the test system, hover your mouse over the GPA Monitor icon, and you’ll see the IP address of that system. Make a note of this address; you’ll be using it soon. At this point, you don’t need anything else running on the test system.

On the analysis system, click on the GPA Monitor, and pick “System Analyzer”. System Analyzer will start up, and ask where to connect. The first time you use it, it’ll say <This Machine>

Clear that text, enter the IP address of your test system, and click Connect. After System Analyzer connects, you’ll see a summary of the different ways you might study what’s happening on your test target system.

NOTE: If you can’t connect from the analysis system, please don’t simply run System Analyzer on the test machine to collect your data. It has a feature-rich GUI which can slow down your game if it’s running on the same system. When you must run on a single system, use the GPA System Analyzer Heads Up Display (HUD).

In the System Profiling category, you’ll see System View. That’s not quite the view you want for studying your game, since it shows only the generic behavior of everything running on your system. To study your game directly, you’ll want to pick something else.

Now, you can start your game on the test system. When you look at System Analyzer, you’ll see a new category for User Applications, along with your game. It doesn’t matter exactly what you’re doing in your game yet, it just needs to be running.

In this case, we’re running the sample game CityRacer. You should see your game show up in the User Applications, like CityRacer does here.

If your game doesn’t show up, check the GPA Monitor’s Preferences setting, and enable Auto-detect launched applications. If it still doesn’t show up, go to the GPA Forum to discuss.

Collect data and study

Now that your game is running, click on its name to get ready to study it in real time.

You’ll see a long list of metrics on the left, some strip charts on the right, and some State Overrides you can use to study the behavior of your game. At the top, there are several command buttons and some summary stats.

Now, set up the metrics you want to watch in real time. Find a metric on the left, and drag it into one of the charts on the right. You can view more metrics by dragging a new metric in between the others, or you can display multiple metrics in one chart with <ctrl>-Click.

To start, show these metrics:

  • Target App CPU Load (in the CPU section) – your game’s CPU use
  • FPS (in the DirectX section) – the game’s instantaneous frame rate, as well as averages over time
  • GPU Busy (in the GPU section) – how heavily your game is using the GPU
  • GPU Frequency (in the GPU section) – shows whether the GPU is running at its maximum frequency or is throttled back
Later, you can study other metrics.
Once you have these metrics displayed in System Analyzer, turn your attention back to your game. Ensure your configuration is the way you want (we recommend you set resolution to >= 1366×768), with Medium quality settings, to give a good performance baseline and show good playability.

Start playing your game and watch the System Analyzer display. Does the performance data look like you expect? GPU-bound games will tend to have fairly high GPU Busy values and GPU frequency will usually stay at the maximum for that part. If you want to know details about your CPU with its integrated GPU, you can discover some hardware details with a tool like CPU-Z and then check those on http://ark.intel.com/.


When you feel like System Analyzer is showing the right data, continue playing the game, and press the CSV button at the top. Wait about 30 seconds and press it again. The exact time isn’t important, but you should collect data long enough to give a good average across your typical gameplay. You’ve just captured a 30-second summary of the data shown in System Analyzer, and saved it into a comma-separated value file.


Now, press the camera icon at the top of System Analyzer. You’ve just taken a frame capture of your game.

If you have different parts of your gameplay to study, repeat those two steps (CSV and frame capture) as needed.

Reviewing your results
Now that you have your data, what should you do with it? Both file types are captured in your “My Documents/GPA_<release>” folder, but the CSV file is stored on the analysis machine and the frame capture is stored on the test machine (it can be quite large). Each file is automatically named with the executable name plus the data and time it was recorded.

For a CSV file, open it (with a text editor or spreadsheet tool) and look at it, and check if it shows what you expected. You should see a column heading for each piece of data that you were showing in System Analyzer, and a row for every sample taken during your 30-second interval.
For the frame capture, you can view it in GPA Frame Analyzer. If you prefer, you can open Frame Analyzer from the analysis machine, giving it the IP address of your test machine like you did with System Analyzer, but it may take a while to copy and open. Faster is to open it on the test machine, but make sure you close your game before opening the frame. Since Frame Analyzer renders the frame in realtime, its performance will be altered if the game is competing with it.

To share your test results with a partner, zip up both files and post to a file sharing site like Dropbox or your own FTP site.

Digging deeper
Now that you have seen a small sample of GPA features, dig deeper.

In System Analyzer, study all the metrics in realtime that might interest you. Collect CSV files and do offline analysis of them, looking for patterns. Use the Overrides to check the various things that might be bottlenecks in your game. Collect multiple frames to study in Frame Analyzer, and collect CPU traces to study in Platform Analyzer (something we didn’t discuss here).

In Frame Analyzer, click different units of work (“ergs”) at the top to see what’s happening in them. Each corresponds to a DirectX call, like a Draw, Clear, etc. You can visualize that work differently, based on some selectors at the top, and you can look at the details of each call with the render target view and detail tabs at the bottom. Find the items you want to understand better, and start experimenting with them. You can do many experiments inside Frame Analyzer, and get realtime feedback on how that would change your frame.

We hope these tools help you better understand how your game performs, and guide you toward making it run the best that it can!

Read more >

Intro to Touch on Ultrabook: Getting started

Touch screens were once an exotic way to interact with special devices, but they’re becoming an everyday part of devices and computers. In addition to phones and tablets, more laptops and convertible computers now include touch screens. As we approach the release of Windows 8, we’ll see new Ultrabook designs that include touch screens. We’ll [...] Read more >