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While I'm not thrilled to add new frame types for every sort of thing, I think having this will be relatively useful so we can improve decoding operations. This adds SysprofCapturePidRoot which lets us specify a root directory on the host system for which is the real root (/) of the PID. This can be useful when reconstructing overlays for containers and you need to direct access to alternate roots. The layer gives us some ability to try to deal with overlayfs, albeit at a very rudimentary level. In most cases I anticipate we just deal with the main root and ignore overlays until necessary.
Sysprof is a sampling profiler that uses a kernel module to generate stacktraces which are then interpreted by the userspace program "sysprof".
See the Sysprof homepage for more information.
Merge requests and bug reports should be sent to sysprof's repository on GNOME's GitLab instance. For general discussion and questions, you can create a new topic in GNOME's Discourse.
The former mailing list is archived in https://mail.gnome.org/archives/sysprof-list/.
Debugging symbols
The programs and libraries you want to profile should be compiled
with -fno-omit-frame-pointer and have debugging symbols available,
or you won't get much usable information.
Building Sysprof
You need some packages installed. The package names may vary depending on your distribution, the following command works on Fedora 25:
sudo dnf install gcc gcc-c++ ninja-build gtk3-devel
Then do the following:
meson --prefix=/usr build
cd build
ninja
sudo ninja install
WARNING: ninja install will mostly install under the configured install
prefix but installs systemd service configuration directly in the system
default location /usr/lib/systemd so it won't work without root privileges,
even if the install prefix is a user-owned directory.