Orbit consists of two parts - the frontend and the collector, also called the service. The collector is responsible for instrumenting the target process and recording profiling events which are then streamed to the frontend, also called the UI.
The communication between frontend and collector is handled by a gRPC connection. gRPC uses HTTP 2.0 as its base communication layer. When talking to a Stadia instance we wrap that once more into an SSH tunnel.
The frontend is supported on Windows 10 and Linux. The collector currently only works on Linux.
Previous versions of Orbit supported profiling on Windows, but due to the priority shift towards Stadia this support is currently in a non-working state. There are plans to bring it back, but at this point we can't commit to any time schedule.
If you want to try profiling on Windows, we recommend you to download the older 1.0.2 release from GitHub's releases page.
To build Orbit you need a compiler capable of C++17. The following ones should be fine.
- GCC 9 and above on Linux
- Clang 7 and above on Linux
- MSVC 2019 and above on Windows (MSVC 2017 is no longer supported by some dependencies)
All our third-party libraries and dependencies are managed by conan.
There are some exceptions. On Linux, we rely by default on the distribution's Qt5
and Mesa installation. This can be changed by modifying the conan package options
system_qt and system_mesa, but we recommend to go with the distribution provided
Qt package. You will need at least version 5.12.4 of Qt. The point release is important
because it resolves a known issue. Note,
that Ubuntu 18.04 LTS comes with Qt 5.9 which is NOT sufficient. Ubuntu 20.04 LTS is
fine though.
In case you still want to have Qt provided by conan, the simplest way to do that will be
to change the default values of these two options.
Check out conanfile.py. There is a python dictionary called default_options
defined in the python class OrbitConan.
On Windows you have the choice to either let Conan compile Qt from source or use one of the prebuilt distributions from The Qt Company. (Note that as of writing this, you need to register to download the distribution packages.)
We recommend to use a prebuilt distribution since compiling from source can take several hours.
If you decide to compile from source, you don't have to prepare anything. You can skip over the next paragraph and go to "Building Orbit".
If you decide to use a prebuilt Qt distribution, please download and install it yourself. Keep in mind the prebuilt has to match your Visual Studio version and architecture. You also have to install the QtWebEngine component which is usually not selected by default in the installer.
As of writing this the minimum supported Qt version is 5.12.4 but this might change.
We recommend the version which we also compile from source. It can be found by checking
conanfile.py. Search for self.requires("qt/. The version can be found after that string.
As a next step you have to tell the Orbit build system where Qt is installed by
setting an environment variable Qt5_DIR. It has to point to the directory
containing the CMake config file Qt5Config.cmake. For Qt 5.15.0 installed to
the default location the path is C:\Qt\5.15.0\msvc2019_64\lib\cmake\Qt5;
You don't have to set that variable globally. It's fine to set it in a local PowerShell when starting the bootstrapping script:
$Env:Qt5_DIR="C:\Qt\5.15.0\msvc2019_64\lib\cmake\Qt5"
.\bootstrap-orbit.ps1The value of Qt5_DIR is persisted in the default conan profiles. You can
call conan profile show default_relwithdebinfo (after running bootstrap)
to see the value of Qt5_DIR.
If you have pre-existing default_*-profiles and want to switch to prebuilt
Qt distributions you have to either delete these profiles - the build script
will regenerate them - or you can manually edit them.
A default profile with Qt compiled from source is pretty much empty:
# default_relwithdebinfo
include(msvc2019_relwithdebinfo)
[settings]
[options]
[build_requires]
[env]
A default profile prepared for a prebuilt Qt package has two extra lines:
# default_relwithdebinfo
include(msvc2019_relwithdebinfo)
[settings]
[options]
OrbitProfiler:system_qt=True
[build_requires]
[env]
OrbitProfiler:Qt5_DIR="C:\Qt\5.15.0\msvc2019_64\lib\cmake\Qt5"
You can find all the conan profiles in %USERPROFILE%\.conan\profiles.
Orbit relies on conan as its package manager. Conan is written in Python3,
so make sure you have either Conan installed or at least have Python3 installed.
The bootstrap-orbit.{sh,ps1} will try to install conan via pip3 if not
installed and reachable via PATH. Afterwards it calls build.{sh,ps1} which
will compile Orbit for you.
On Linux, python3 should be preinstalled anyway, but you might need to install
pip (package name: python3-pip).
On Windows, one option to install Python is via the Visual Studio Installer.
Alternatively you can download prebuilts from python.org
(In both cases verify that pip3.exe is in the path, otherwise the bootstrap
script will not be able to install conan for you.)
Like mentioned before, the collector currently only works for Linux. So the following only applies there:
To obtain scheduling information, the collector needs to run as root:
sudo ./build_default_relwithdebinfo/bin/OrbitService # Start the collectorAfter the collector runs you can start the frontend from a different shell.
./build_default_relwithdebinfo/bin/Orbit --localThe frontend currently has no graphical user interface to connect to a generic
remote instance. Only Stadia is supported as a special case. That's why you need
to start the frontend in --local mode. This will instruct Orbit to connect to the
service at localhost on port 44765.
If you needed remote profiling support you could tunnel the mentioned TCP port through a SSH connection to an arbitrary Linux server. There are plans on adding generic SSH tunneling support but we can't promise any timeframe for that.
We use clang-format to achieve a consistent code styling across
the whole code base. You need at least version 7.0.0 of clang-format.
Please ensure that you applied clang-format to all your
files in your pull request. Otherwise a presubmit check will fail
and unfortunately only Googlers have access to the detailed log.
On Windows, we recommend getting clang-format directly from the
LLVM.org website. They offer binary packages of clang, where
clang-format is part of.
Visual Studio 2017+ ships clang-format as part of the IDE though.
(https://devblogs.microsoft.com/cppblog/clangformat-support-in-visual-studio-2017-15-7-preview-1/)
On most Linux distributions, there is a dedicated package called clang-format.
Most modern IDEs provide clang-format integration via either an extension
or directly.
A .clang-format file which defines our specific code style lives in the
top level directory of the repository. The style is identical to the Google
style.
As mentioned above we use clang-format to enforce certain aspects of code
style. The Google C++ style guide we are following in that can be found
here. It includes brief
discussions or rationales for all the style decisions.
Beyond what it is in the style guide we agreed to a few more additional rules specific to the Orbit project:
We use [[nodiscard]] for (almost) all new class methods and free functions
that return a value. If you encouter a use case where it makes no sense or
hurts readability feel free to skip it though.
We do not touch existing code merely to add [[nodiscard]] though.
For error handling we use ErrorMessageOr<T> from
Result.h.
This class serves the same purpose as absl::StatusOr<T>. We thought about
switching to absl but currently the advantage does not seem large enough to
warrant the effort. So for now we stick with ErrorMessageOr<T>.
In cases where no error message needs to be returned it is perfectly fine to
use std::optional.
Currently our code is compiled with exceptions but we strive towards a world
with no exceptions. Particularly we don't use methods from std that throw
exceptions but prefer the variants returning error codes (e.g. in
std::filesystem).
We place all code belonging to a module named ModuleName or OrbitModuleName
inside the top-level namespace orbit_module_name. All namespaces start with
the orbit_ prefix. We do not use nested namespaces.
Exclusively for code that needs to be in a .h file public to a module (i.e.,
in the include directory) even if that code shouldn't be used by other
modules, we use the top-level namespace orbit_module_name_internal instead.
This is not nested inside orbit_module_name.
bootstrap-orbit.{sh,ps1} performs all the tasks which have to be done once per developer machine.
This includes:
- Installing system dependencies
- Installing the correct version of conan if necessary.
- Installing the conan configuration (which changes rarely).
Afterwards bootstrap-orbit.{sh,ps1} calls build.{sh,ps1}.
build.{sh,ps1} on the other hand performs all the tasks which have to be done
once per build configuration. It creates a build directory, named after the
given conan profile, installs the conan-managed dependencies into this build folder,
calls cmake for build configuration and starts the build.
Whenever the dependencies change you have to call build.{sh,ps1} again.
A dependency change might be introduced by a pull from upstream or by a switch
to a different branch.
It might occur to you that even though you called build.{sh,ps1} your build still
fails with a weird error message. Most of the time this is due to outdated but cached
information managed by CMake. The simplest way to resolve that problem is to make
a clean build by deleting the build directory and calling build.{sh,ps1}.
build.{sh,ps1} can initialize as many build configurations as you like from the
same invocation. Just pass conan profile names as command line arguments. Example for Linux:
./build.sh clang7_debug gcc9_release clang9_relwithdebinfo ggp_release
# is equivalent to
./build.sh clang7_debug
./build.sh gcc9_release
./build.sh clang9_relwithdebinfo
./build.sh ggp_releasebuild.{sh,ps1} is not meant for incremental builds. It should be called only once to initialize
a build directory. (Check out the previous section for more information on what build.{sh,ps1}
does.)
For incremental builds, switch to the build directory and ask cmake to run the build:
cd <build_folder>/
cmake --build . # On Linux
cmake --build . --config {Release,RelWithDebInfo,Debug} # On WindowsAlternatively, you can also just call make on Linux. Check out the next section on how to
enable building with ninja.
Note: Linux only for now! On Windows you have to use MSBuild.
If you want to use ninja, you cannot rely on the build.sh script, which automatically
initializes your build with make and that cannot be changed easily later on.
So create a build directory from scratch, install the conan-managed dependencies
and invoke cmake manually. Here is how it works:
Let's assume you want to build Orbit in debug mode with clang-9:
mkdir build_clang9_debug # Create a build directory; should not exist before.
cd build_clang9_debug/
conan install -pr clang9_debug ../ # Install conan-managed dependencies
cp ../third_party/toolchains/toolchain-linux-clang9-debug.cmake toolchain.cmake # Copy the cmake toolchain file, which matches the conan profile.
cmake -DCMAKE_TOOLCHAIN_FILE=toolchain.cmake -G Ninja ../
ninjaPlease be aware that it is your responsibility to ensure that the conan profile is compatible with the toolchain parameters cmake uses. In this example clang9 in debug mode is used in both cases.
You can also manually pass the toolchain options to cmake via the command line:
mkdir build_clang9_debug # Create a build directory; should not exist before.
cd build_clang9_debug/
conan install -pr clang9_debug ../ # Install conan-managed dependencies
cmake -DCMAKE_CXX_COMPILER=clang++-9 -DCMAKE_C_COMPILER=clang-9 -DCMAKE_BUILD_TYPE=Debug -G Ninja ../
ninjaIn CLion, the IDE itself manages your build configurations, which is incompatible with our build.{sh,ps1}
script. That means, you have to manually install conan dependencies into CLion's build directories
and you have to manually verify that the directory's build configuration matches the used conan profile
in terms of compiler, standard library, build type, target platform, etc.
cd build_directory_created_by_clion/
conan install -pr matching_conan_profile ..After that, you can trigger a rerun of cmake from CLion and it will now be able to pick up all the missing
dependencies.
This process can be automated by the CLion Conan Extension.
After installing the extension, it will take care of installing conan dependencies into your CLion build directories, whenever necessary. The only task left to you is to create a mapping between CLion build configurations and conan profiles. Check out this blog post on how to do it.
Add -DCMAKE_CXX_FLAGS=-fsized-deallocation to Settings -> Build, Execution, Deployment -> CMake -> CMake options.
This flag is needed because Orbit's codebase makes use of C++14's sized-deallocation feature
which is not enabled by default on the clang compiler.
Visual Studio has this concept of having multiple build configurations in the same build directory. This concept is not very wide-spread on buildsystems coming from the Unix world. Both CMake and Conan have support for it, but some of our dependencies currently do not support it.
That means, currently you can't have debug and release builds in the same build folder! Please ensure that Visual Studio is set to the build configuration which matches your build- folder's conan profile. Non-matching build configurations will result in a lot of linker errors.
There is a Conan Extension for Visual Studio, which is currently under development, but should be able to help you, when you develop on Visual Studio.
Visual Studio Code uses configuration files to specify tasks that can be executed. These files are provided in the contrib/.vscode folder. To enable building from Visual Studio Code, simply copy the whole folder into the root directory with the name .vscode:
cp -r contrib/vscode .vscodeConan installs cmake as a build dependency automatically, but won't make it available in the PATH.
If you want to use conan's cmake installation, you can use the virtualenv generator to create
a virtual environment which has cmake in its PATH:
cd my_build_folder/
conan install -pr my_conan_profile -g virtualenv ../
source ./activate.sh # On Linux (bash) or on Windows in git-bash
.\activate.bat # On Windows in cmd
.\activate.ps1 # On Windows in powershell
cmake ... # CMake from conan is now availableThere is also a deactivate.{sh,bat,ps1} which make your shell leave the virtual environment.
This message or a similar one indicates that your build profiles are outdated and need to be updated. You can either just call the bootstrap script again or you can manually update your conan config:
conan config install third_party/conan/configs/[windows,linux]Orbit supports loading symbols from your workstation. Simply add directories that contain debugging symbols to the SymbolPaths.txt file. This file can be found at
- Windows:
C:\Users\<user>\AppData\Roaming\OrbitProfiler\config\SymbolPaths.txt - Linux:
~/orbitprofiler/config/SymbolPaths.txt
The symbols file must named in one of three ways. The same fname as the binary (game.elf), the same name plus the .debug extension (game.elf.debug) or the same name but the .debug extension instead of the original one (game.debug). To make sure the binary and symbols file have been produced in the same build, Orbit checks that they have a matching build id.
Cross compilation is supported on Windows and Linux host systems.
Note: Cross compiling the UI is not supported.
Note: Since the GGP SDK is not publicly available, this only works inside of Google, at least for now.
Call the script bootstrap-orbit-ggp.{sh,ps1} which creates a package out of the GGP
SDK (you do not need to have the SDK installed for this to work, but you will need it
for deployment), and compiles Orbit against the toolchain from the GGP SDK package.
Finally, build_ggp_release/package/bin/OrbitService can be copied over
to the instance:
ggp ssh put build_ggp_release/package/bin/OrbitService /mnt/developer/before the service can be started with:
ggp ssh shell
> sudo /mnt/developer/OrbitService