This is the official Linux port of the DTrace tracing tool.
The source is posted here on github.com in the hope that it increases the visibility for our work and to make it even easier for people to access the source. We also use this repository to work with developers in the Linux community.
The main development branch is 2.0-branch-dev.
We provide prebuilt DTrace userspace packages for Oracle Linux 7 and Oracle Linux 8, using the UEK6 kernel. These packages are based on the Oracle Linux specific release branch 2.0-branch.
The latest packages can be obtained from the following Oracle Linux yum server repositories:
- Oracle Linux 7 (x86_64) UEK Release 6 (kernel version 5.4.17): https://yum.oracle.com/repo/OracleLinux/OL7/UEKR6/x86_64
- Oracle Linux 7 (aarch64) UEK Release 6 (kernel version 5.4.17): https://yum.oracle.com/repo/OracleLinux/OL7/UEKR6/aarch64
- Oracle Linux 8 (x86_64) UEK Release 6 (kernel version 5.4.17): https://yum.oracle.com/repo/OracleLinux/OL8/UEKR6/x86_64
- Oracle Linux 8 (aarch64) UEK Release 6 (kernel version 5.4.17): https://yum.oracle.com/repo/OracleLinux/OL8/baseos/latest/aarch64
Source code for the UEK kernel is available on github in the linux-uek repo.
- 1. License
- 2. How to Build DTrace
- 3. Testing
- 4. How to Run DTrace
- 5. Questions
- 6. Pull Requests and Support
UPL (Universal Permissive License) https://oss.oracle.com/licenses/upl/
The build instructions focus on building DTrace for the upstream Linux kernel. We will use the 5.8.1 release, but the instructions apply to most recent Linux kernel versions.
Please read this section carefully before moving over to the build documentation to ensure your environment is properly configured.
CTF type support requires installation of supporting libraries and development headers. CTF library development is handled as a separate project.
For more information about how to build and install the libraries from source code, please visit libdtrace-ctf.
The kernel build depends on the following packages that may not be installed on the system yet. The table below gives the package names for Debian and Oracle Linux as examples.
| Prerequisite | Debian | Oracle Linux |
|---|---|---|
| glib2 | libglib2.0-dev | glib2-devel |
| libdw | libdw-dev | elfutils-devel |
| libelf | libelf-dev | elfutils-libelf-devel |
DTrace currently depends on a few extra kernel features that are not available in the upstream kernel:
- CTF type information extraction
- /proc/kallmodsyms
- New system call: waitfd()
Patches that implement these features are available from the v2/* branches in our Linux kernel repository for features that DTrace uses: https://github.com/oracle/dtrace-linux-kernel
The customary way to obtain these patches is to clone an appropriate upstream kernel version (5.8.1 or later) and to merge our updated tree into it. The patch set is quite small, but may need some tweaking if it is being merged into a newer tree. We occasionally push a new patched tree to our github repo, so do look around to see if there is a better match.
Typical steps to patch a kernel with the add-on features are:
# Start with a clone from the upstream kernel repository.
git clone https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git
# Add the repository with the add-on features as a remote.
git remote add addons https://github.com/oracle/dtrace-linux-kernel
git remote update addons
# Check out the latest 5.8.* kernel.
git checkout -b 5.8-addons origin/linux-5.8.y
# Merge the add-on features into the upstream kernel tree.
git merge --no-edit addons/v2/5.8.1
Oracle Linux's UEK6 provides a simple alternative if you don't want to patch your own kernel.
Building of a patched kernel from sources is also straightforward.
Please consult Documentation/process/changes.rst in the kernel source tree
to ensure all required dependencies are installed first. The following steps
should build and install the kernel.
# Start with your preferred .config options. Features DTrace needs should
# enable themselves automatically.
make olddefconfig
make
# This step will produce vmlinux.ctfa, which holds all CTF data for the kernel
# and its modules.
make ctf
# Install with root privileges.
sudo make INSTALL_MOD_STRIP=1 modules_install
sudo make install
It is preferred (but not required) to reboot into your new kernel before trying to build DTrace.
A few remaining packages are required either for building or at runtime. They should be part of most Linux distributions today and can be installed via the package manager of your distro. The table below gives package names for Debian and Oracle Linux.
We assume that the packages needed to build libdtrace-ctf and the kernel remain installed so they are not repeated here.
For building:
| Prerequisite | Debian | Oracle Linux |
|---|---|---|
| glibc headers | libc6-dev | glibc-headers |
| glibc (static) | (in libc6-dev) | glibc-static |
| glibc (32-bit dev) | libc6-dev-i386 | glibc-devel.i686 |
| bison | bison | bison |
| flex | flex | flex |
| BPF gcc | gcc-bpf | gcc-bpf-unknown-none |
| BPF binutils | binutils-bpf | binutils-bpf-unknown-none |
| libpcap dev | libpcap-dev | libpcap-devel |
At runtime:
| Prerequisite | Debian | Oracle Linux |
|---|---|---|
| wireshark | wireshark | wireshark |
The simplest way of building DTrace is booting into your new kernel with the add-on features DTrace expects and issuing the following commands from the DTrace source tree:
make
sudo make install
Some distributions install the BPF gcc and binutils under different names. You can specify the executables to use using the BPFC and BPFLD variables. E.g. on Debian you would use:
make BPFC=bpf-gcc BPFLD=bpf-ld
sudo make install
In this scenario the build system expects that kernel sources can be found at
/lib/modules/$(uname -r)/build. It is also expected that the kernel used for
userspace build is compatible with the utils (the exported userspace headers in
the include/uapi/linux/dtrace are compatible with the utils version being
built).
A testsuite is provided in the source tree. It is run using make in conjunction with one of the following targets:
| target | description |
|---|---|
check-verbose |
Tests binaries from build directory. Prints result of every tests. |
check-installed-verbose |
Tests binaries installed in the system. Prints result of every tests. |
Example:
sudo make check-verbose
Logs from test runs are stored in test/log/<run_number>/.
The most recent logs are also available by via the test/log/current/ symbolic link.
The testsuite itself has more dependencies that need to be installed. The full list is available in the dtrace.spec file.
The dtrace binary is installed in /usr/sbin/dtrace.
Currently, you can only run dtrace with root privileges.
Be careful not to confuse the utility with SystemTap's dtrace script,
which is installed in /usr/bin/dtrace.
For questions, please check the dtrace-devel mailing list.
We currently do not accept pull requests via GitHub, please contact us via the mailing list above.
The source code for DTrace is published here without support. Compiled binaries are provided as part of Oracle Linux, which is free to download, distribute and use. Support for DTrace is included in Oracle Linux support subscriptions. Individual packages and updates are available on the Oracle Linux yum server.