Profiling#

Kit-based applications come bundled with a profiler interface to instrument your code, for both C++ and Python. Multiple profiler backend implementations are supported:

  • NVTX

  • ChromeTrace

  • Tracy

Easy Start#

  1. Enable the omni.kit.profiler.window extension.

  2. Press F5 to start profiling, then press F5 again to stop profiling and get a trace opened in Tracy.

Press F8 to open the profiler window, where you can perform additional operations such as enabling the Python profiler, browsing traces, etc.

All traces are saved into one folder (can be found in the Browse section of the profiler window). They can be viewed with either Tracy or Chrome (by navigating to chrome://tracing).

Note

Both F5 and F8 have an entry in the top menu.

Profiling Backends#

Chrome Trace#

Run the Kit-based application using the following settings to produce a trace file named mytrace.gz in the directory where the executable is located:

kit.exe [your_configuration] \
    --/app/profilerBackend="cpu" \
    --/app/profileFromStart=1 \
    --/plugins/carb.profiler-cpu.plugin/saveProfile=1 \
    --/plugins/carb.profiler-cpu.plugin/compressProfile=1 \
    --/plugins/carb.profiler-cpu.plugin/filePath="mytrace.gz"

Then, using the Google Chrome browser, navigate to chrome://tracing to open a trace file and explore areas of interest.

Tracy#

On Demand#

  1. Enable the omni.kit.profiler.tracy extension.

  2. Select Profiling->Tracy->Launch and Connect from the menu.

Note: The omni.kit.profiler.tracy extension contains the currently supported version of Tracy (v0.9.1), which can also be downloaded from GitHub.

From Startup#

Run the Kit-based application using the following settings:

kit.exe [your_configuration] \
    --/app/profilerBackend="tracy" \
    --/app/profileFromStart=true

Run Tracy and click the “Connect” button to start capturing profiling events.

You can also convert a chrome trace profile to Tracy format using import-chrome.exe tool it provides. There is a helper tool to do that in repo_kit_tools, it downloads Tracy from packman and opens any of those 3 formats:

repo tracetools tracy mytrace.gz
repo tracetools tracy mytrace.json
repo tracetools tracy mytrace.tracy

Multiplexer#

You can enable multiple profiler backends at the same time.

Run the Kit-based application using the following settings:

kit.exe [your_configuration] \
    --/app/profilerBackend=[cpu,tracy] \
    {other_settings_specific_to_either}

The multiplexer profiler will automatically detect any IProfiler implementations that are loaded afterwards, for example as part of an extension.

If the --/app/profilerBackend setting is empty, the multiplexer profiler will be used as the default, along with the cpu profiler behind it.

Instrumenting Code#

To instrument C++ code, use the macros from the Carbonite Profiler, e.g.:

#include <carb/profiler/Profile.h>

constexpr const uint64_t kProfilerMask = 1;

void myfunc()
{
    CARB_PROFILE_ZONE(kProfilerMask, "My C++ function");

    // Do hard work here.
    // [...]
}

For Python code, use the Carbonite Profiler bindings:

import carb.profiler

# Using the decorator version:

@carb.profiler.profile
def foo():
    pass


# Using explicit begin/end statements:

def my_func():
    carb.profiler.begin(1, "My Python function")

    # Do hard work here.
    # [...]

    carb.profiler.end(1)

Automatic Python Profiler#

Carbonite profiler includes a native Python profiler. It uses Python’s CAPI to hook into the Python interpreter and profile all function calls. It is disabled by default as it may introduce some overhead. There are two ways to enable it:

  1. Set CARB_PROFILING_PYTHON=1 environment variable.

  2. Use API: carb.profiler.acquire_profiler_interface().set_python_profiling_enabled(True).

All Python function calls will be profiled and shown in the profiling trace with (Python) postfix.

Profiling Startup Time#

Kit includes a handy shell script to profile app startup time: profile_startup.bat.

It runs an app with profiling enabled, quits, and opens the trace in Tracy. Pass the path to the app kit file and other arguments to it. E.g.:

profile_startup.bat path/to/omni.app.full.kit --/foo/bar=123

To enable python profiling set environment variable CARB_PROFILING_PYTHON=1 or uncomment that line in the script.

On this page