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Enable optional features for QNX

Enable optional features to improve your application performance.
Read time 7 minutesLast updated 12 days ago
You can enable the following optional features to improve the performance of your applications.

Shader cache persistence for GLES3

QNX supports binary shader caching on the device where the Unity Player is installed. Reusing a compiled shader binary from a cache file is usually faster than compiling the shader again. This results in faster setup times for each shader program during subsequent app restarts or scene reloads. The cache is created at runtime after you load a shader. As this cache is written to the temporary folder:
[TEMP]/[COMPANY_NAME]/[PROJECT_NAME]/UnityShaderCache/
, it can be wiped when you restart the system.
To use shader caching when your system restarts, copy the cache into the Player data by following these steps:
  1. Deploy the Unity Player to the target system.
  2. Run the application and make sure all shaders are touched.
  3. Copy all the files from 
    [TEMP]/[COMPANY_NAME]/[PROJECT_NAME]/UnityShaderCache/
    to 
    [PATH_TO_PLAYER]/Data/UnityShaderCache/
    .

Pipeline cache persistence for Vulkan

QNX supports binary Vulkan pipeline caching on the device where the Unity Player is installed. In Vulkan, pipeline caching combines a compiled shader with the current graphics state. Reusing such shader from a cache file is significantly faster than the complex process involved in compiling it. This results in faster setup times for each shader program and graphics state combination during subsequent app restarts or scene reloads. The binary Vulkan pipeline cache is created at runtime when you use Vulkan pipelines. As this cache is written to the temporary 
[TEMP]/[COMPANY_NAME]/[PROJECT_NAME]/vulkan_pso_cache.bin
file, you can wipe it when you restart the system.
To use pipeline caching when your system restarts, copy the cache into the Player data by following these steps:
  1. Deploy the Unity Player to the target system.
  2. Run the application and make sure all pipelines are being used.
  3. Copy 
    [TEMP]/[COMPANY_NAME]/[PROJECT_NAME]/vulkan_pso_cache.bin
    file to 
    [PATH_TO_PLAYER]/Data
    .
Notes:
  • Refresh the cache every time you update the Player.
  • As the cache is device-specific, only share it between devices with the exact same hardware and software configuration.
  • To specify the location of the read-write cache, use 
    platform-hmi-gfx-cache-path
    . For more information, refer to Command line arguments.
  • When using pipeline caching, the method calls to create graphics pipelines resolve significantly faster, thereby reducing subsequent scene loading times. To measure performance gains when using pipeline caching, compare the time it takes for the first frame to load when the scene reloads or app restarts.
  • Using a cache slightly increases early engine initialization time. You can observe this increase in startup timing data when you use the 
    -platform-hmi-log-startup-times
    command line argument. However, using the cache reduces the time to render the first frame.
  • Use ShaderVariantCollection.WarmUp() to compile or load shaders into memory ahead-of-time for subsequent use. Call this method when CPU resources are available, such as during app startup to ensure shaders are ready when needed and to prevent lags during gameplay. However, this might increase the start-up time as Unity processes the shaders.

Command line arguments

You can launch the Unity QNX Player from the command line and pass arguments to change how the Player executes.
Note
All command line arguments have precedence over the settings configured in the Unity Editor.

Command line argument

Description

-platform-qnx-graphics-conf
Configure the path to the 
graphics.conf
to override auto detection.
-platform-hmi-force-srgb-blit
Change the 
Force SRGB blit
setting to control whether Gamma Color Space (sRGB) is used instead of Linear Color Space during rendering. For more information, refer to Player Settings > Rendering > Force SRGB blit.
-platform-hmi-log-startup-times
Log the Player's startup timing data. This argument is required to use the startup profiling tool 
-platform-hmi-quit-after-frame N
.
-platform-hmi-quit-after-frame
Log the Player's startup timing data for the first 
N
frames and automatically exit the Player after rendering the 
N
th frame. 
N
represents the number of frames for which you want to log the Player's startup time. Use this argument to profile the Player's startup performance.

Note: This argument has an effect only when 
-platform-hmi-log-startup-times
is enabled.
-platform-hmi-single-gl-context
Disable context sharing for OpenGL ES. By default, Unity uses two OpenGL ES contexts, one for startup and another for rendering. This argument forces Unity to use a single context instead. Use this argument to detect and troubleshoot graphics drivers issues.

Note: This argument disables multi-display support.
-platform-hmi-cpu-configuration <configuration>
Specify a CPU configuration for the Player. This argument expects a string containing a combination of the letters: H (high performance core), L (low performance core) and/or D (disable core). The string defines the performance mode of each CPU core.

For example, 
DHLL
on a 4-core CPU disables the first core, assigns the second core as high performance, and configures the third and forth as low performance. For more information, refer to Player Settings > Configuration > CPU configuration.
-platform-hmi-player-data-path
Enter the directory path on the system where you want to save the 
.config
and log files. For more information, refer to Player Settings > Configuration > Player Data path.
-platform-hmi-force-vsync-count [C]
Define the number of vertical syncs allowed to pass between each frame. Set it to 
0
to disable vsync completely, or set it 
-1
to use the value set in 
QualitySettings
.
-platform-hmi-enable-signal-handlers
Configure Unity engine's signal handler setup for embedded platforms. The default value is 
1
which enables Unity's signal handlers. If crash handling or core dump creation doesn't work correctly, disable this argument by setting it to 
0
.
-platform-hmi-gfx-cache-path <path>
Sets a custom path for the engine to store the GLES shader cache or Vulkan pipeline cache depending on the graphics back-end and platform capabilities. The custom path has precedence over the persistent cache for GLES3 and Vulkan.

Note: The path provided must exist and be writable.

The player log file (
Player.log
) contains information about issues and successful usage.

Startup time logging

Startup time logging is the length of time that it takes an application to start up. It's often used as a critical metric for system safety and regulatory requirements.
Startup time logging in QNX devices include the duration or total time from the time the application launches. There are two types of Startup time logging:
  • Real: This is the actual wall or clock time, similar to a stopwatch used for calculating the time.
  • User: This is the time an application or one of its threads has spent on a CPU core. This can be higher than the Real time if multiple threads are busy when an application is starting up.

Example output

[TIMING::STARTUP] Initial probing done: Real: 19 ms | User: 11 ms[TIMING::STARTUP] SDL Initialized: Real: 64 ms | User: 54 ms[TIMING::STARTUP] Scripting runtime loaded: Real: 97 ms | User: 86 ms[TIMING::STARTUP] Plugins loaded: Real: 97 ms | User: 87 ms[TIMING::STARTUP] Engine initialized (nogfx): Real: 104 ms | User: 94 ms[TIMING::STARTUP] Player Prefs loaded: Real: 104 ms | User: 94 ms[TIMING::STARTUP] Screen initialized: Real: 139 ms | User: 112 ms[TIMING::STARTUP] Engine initialized (gfx): Real: 187 ms | User: 161 ms[TIMING::STARTUP] Gfx initialized: Real: 190 ms | User: 163 ms[TIMING::STARTUP] Input initialized: Real: 190 ms | User: 163 ms[TIMING::STARTUP] SPLASH - Begin: Real: 190 ms | User: 164 ms[TIMING::STARTUP] SPLASH - Primary scene assets loaded (async): Real: 2197 ms | User: 1670 ms[TIMING::STARTUP] SPLASH - All engine initial states established: Real: 2197 ms | User: 1670 ms
Output from a custom event using the Script API
[TIMING::STARTUP] HELLO!!: Real: 2198 ms | User: 1671 ms
When you specify 
platform-hmi-quit-after-frame
command line argument, the log contains the following information up to frame number 
X
, where 
X
is the number of frames after which the application quits.
[TIMING::STARTUP] Frame 1 rendered: Real: 2209 ms | User: 1687 ms
[TIMING::STARTUP] Frame 2 rendered: Real: 2210 ms | User: 1692 ms

Webcam

Note
Unity's support for Webcam in QNX is currently experimental.

Prerequisites

  • QNX 7.1
  • libcamapi
    and its dependencies installed on the system (will be loaded dynamically)
  • Camera supporting 
    NV12
    format
Webcam usage is optional in QNX and it's only supported on QNX 7.1. For more information, refer to the Webcam documentation.

Additional resources