Intel® VTune™ Profiler Performance Analysis Cookbook

Cookbook

  • 2023
  • 12/16/2022
  • Public Content
Contents

Profiling Games built with Unreal Engine* (NEW)

Use this recipe to profile a game built with Unreal Engine. See how you can run
Intel® VTune™
Profiler
 within the Unreal Engine environment to profile your game.
Often, the most important factor that affects the performance of a game is the frame rate. This is the speed with which the GPU renders game graphics. However, the CPU can also impact game performance in several ways:
  • Slow transfer of data to the GPU
  • Slow or unnecessary operations
  • Poor parallelism
With games that use the Unreal Engine (UE), much of the optimization takes place in the Unreal editor. Therefore, it is critical to understand the performance of Unreal Engine-defined tasks. The 4.19 and newer versions of Unreal Engine have the
Intel® VTune™
Profiler
 Instrumentation and Tracing Technology (ITT) API built into the Unreal editor. This recipe demonstrates how you can run
VTune Profiler
 to highlight UE tasks in the editor.

Ingredients

Here are the hardware and software requirements for this performance recipe.
  • Application
    :
    Unreal Engine 4.25.4
    . The sample game in this version of Unreal Engine is the Action RPG tutorial.
  • Tools
    :
    Intel® VTune™
    Profiler
     version 2022 - Hotspots Analysis (using User-Mode Sampling)
    • Starting with the 2020 release, Intel® VTune™ Amplifier has been renamed to
      Intel® VTune™
      Profiler
      .
    • Most recipes in the
      Intel® VTune™
      Profiler
       Performance Analysis Cookbook are flexible. You can apply them to different versions of
      Intel® VTune™
      Profiler
      . In some cases, minor adjustments may be required.
    • Get the latest version of
      Intel® VTune™
      Profiler
      :
  • CPU/GPU
    : 11
    th
     Generation Intel® Core™ i7-1165G7 CPU @ 2.80GHz with Intel® Iris® Xe MAX Graphics
  • Operating system
    : Windows* 11 Enterprise

Build the Game in the Unreal Editor

  1. Open the game in the Unreal editor.
    Build the game in Unreal Engine
  2. Build the game. Make sure to select the
    Development
     Build Configuration and
    Include Debug Files
     options.
    Unreal Engine configuration options

Configure
Intel® VTune™
Profiler
 and Run Hotspots Analysis

  1. Open
    Intel® VTune™
    Profiler
     and click
    New Project
     on the Welcome screen.
  2. Specify a project name and a location for your project.
  3. Click
    Create Project
    .
  4. In the
    Configure Analysis
     window, set these options:
    • In the
      WHERE
       pane, select
      Local Host
      .
    • In the
      Application
       field of the
      WHAT
       pane, enter the path to the game executable.
    • In the
      Application parameters
       field, enter
      -VTune
      .
    Configure Analysis options
  5. (Optional) If you want to skip profiling the start/loading phase of the game,
    • In the
      WHAT
       pane, open the
      Advanced
       section.
    • Set
    • Under
      Limit collected data by
      , set a value in seconds for
      Time from collection end, sec
      . This is the duration (in seconds) before the end of the collection for which
      Intel® VTune™
      Profiler
       should retain the results. The data collected earlier than this time gets discarded.
    Advanced configuration options
  6. In the
    HOW
     pane, select the
    Hotspots analysis type
     and enable user-mode sampling.
  7. Click
    Start
     to run the analysis.
Configure Hotspots Analysis
If you set the
Automatically resume collection after
 option in step 5, only the
Start Paused
 button () is available.

Review Results

When the data collection stops,
Intel® VTune™
Profiler
 finalizes the results. This process may take a few minutes as
Intel® VTune™
Profiler
 finds and resolves debug symbols.
Once results have been finalized, the
Summary
 tab displays information about:
  • Elapsed time
  • Top hotspots
  • Top Unreal Engine tasks
  • Additional insights and guidance
Hotspots summary tab for game in Unreal Engine
Switch to the
Bottom-up
 window to see a list of functions. The default sorting is by descending order of CPU time.
Change the grouping from
Function / Call Stack
 to
Task Domain / Task Type / Function / Call Stack
 to focus on Unreal Engine tasks which were identified by the
Intel® VTune™
Profiler
 Instrumentation and Tracing Technology API (ITT API).
Unreal Engine tasks by Task Domain/Task Type/Function/Call Stack grouping
In this example, there is considerable spin time in the Render and Game threads. Also, nearly half of the overall CPU utilization was spent spinning, or waiting for a resource to return.
The CPU utilization histogram (in the
Summary
 tab) tells us something important. Although this game was running over 100 threads, for the majority of the run, this game only utilized a single CPU or was mostly idle.
From here, you can try to identify whether the high amount of spin is affecting performance negatively. You can also examine how to make use of more CPU capability. Generally games are not expected to consume the full amount of hardware resources, but there is room on this system for more parallelism.
For additional insights into hotspots, open the
Flame Graph
 view to see a graphical representation of call stacks from the top down.
Flame Graph view

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.