Messages in this thread | | | Date | Thu, 15 Nov 2018 22:02:56 -0800 (PST) | From | Kris Van Hees <> | Subject | [RFC] DTrace based on eBPF and other tracing facilities |
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A lot of work has been done on various aspects of the tracing infrastructure in Linux in the past years and with the further development of BPF a quite powerful execution engine has become available as well.
One of the difficulties we have experienced in furthering DTrace on Linux is that we have to duplicate functionality already available in the kernel because that functionality is not easy to make use of.
In the past year or so we have been working towards changing that. There is no point in having multiple projects reinvent the same wheel a couple of times over, especially when there are ways where everyone can benefit from actually cooperating. Our current (lofty) goal is to rework the DTrace implementation that we currently have to make it more modular and less self-sufficient. We are envisioning a future for DTrace where we can leverage its strengths in the areas where it matters most (e.g. very efficient handling of large amounts of kernel probes, well defined and understood D language, user familiarity with existing providers, ...) while building on the existing tracing infrastructure in Linux. That also means that we can contribute better to existing pieces in the infrastructure and work together with other tracing projects to continue to improve tracing on Linux.
Ideally we would like to see an infrastructure where any tracers can attach actions to any kind of probe source, and have data generated according to the actions the tracer associated with the probe source when a specific probe fires. The execution of those actions would be done using BPF.
We believe that this proposal would be a benefit to all because it allows us to pool resources in the areas that really need it. E.g. if we all depend on BPF as execution engine we invariably work together to make it as solid as can be.
Obviously we cannot do this work on our own, and we cannot do it behind closed doors. We've created a github repository for the kernel with DTrace added in at:
https://github.com/ezannoni/dtrace-linux-kernel/tree/master
We also have a branch there with the most recent BPF-based work:
https://github.com/ezannoni/dtrace-linux-kernel/tree/nix/bpf/4.19/helpers
Since most (if not all) tracing tools have similar requirements for what may need to be done when a probe fires, we really want to join forces.
Cheers, Kris
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