[DTrace-devel] Git repo with DTrace support patches

[Kris Van Hees]

On Fri, Jan 19, 2024 at 08:17:42AM +0000, Tomasz K??oczko via DTrace-devel wrote:
> On Fri, 19 Jan 2024 at 03:20, Kris Van Hees <kris.van.hees at oracle.com> wrote:
> 
>     On Fri, Jan 19, 2024 at 01:53:20AM +0000, Tomasz K??oczko via DTrace-devel
>     wrote:
>     > Hi,
>     >
>     > Cannot find where is git repo in which DTrace support is maintained.
>     > Where is that repo?ðY¤"
> 
>     Our development repo is found at https://github.com/oracle/dtrace-utils
> 
> 
> This repo contains only source code of the DTrace tools/libraries.
> My question was about the kernel space part.

As of DTrace 2.0.0 there is no kernel space portion anymore - the current
implementation of DTrace is entirely based on leveraging tracing facilities
in the upstream kernel.  We do make use of CTF and modules.builtin.ranges
data (when available) to improve functionality.  Those patches can be found
in the https://github.com/oracle/dtrace-kernel repo, but just the userspace
component alone provides quite powerful (albeit a bit restricted) tracing
functionality.

> BTW mentioned in README.md for examople https://yum.oracle.com/repo/OracleLinux
> /OL9/UEKR7/x86_64/ contains kernel and user space binary packages but https://
> yum.oracle.com/repo/OracleLinux/OL9/UEKR7/SRPMS do not exist.
> Some of those packages are distributed under GPL licenses so the source version
> should be distributable as well.

There is no requirement to provide SRPMS since the entire kernel tree with the
add-on patches is available from the github repo mentioned in ther README.md:
https://github.com/oracle/dtrace-linux-kernel

> And more questions ..
> 
> As mentioned in README.md OL dnf repo is only binary kernel 5.15.x. How is it
> with kernel 6.6.x/6.7.x support?

As the README.md explains, the patches are provided based on a existing kernel
version, but they certain apply also to newer kernels (possibly with minor
changes).  But feel free to try out DTrace with a 6.6.x or 6.7.x kernel using
the development version found in our repo.

> Latest version dtrace-utils is 2.0.0-1.13.2 which is unacceptable for rpm as
> version string.
> Why 2.13.2 is not used?

When we started the reworking of DTrace based on existing kernel tracing
features rather than using a more invasive set of kernel patches and modules,
we decided not to start a true numbering in a 1.x series until we had better
version parity with the previous version.  As we approach that, the numbering
is set to change very soon.

However, the fact that OL has been using the existing numbering scheme for a
few years now clearly shows that it is actually valid for RPMs.  As you can
see in the dtrace.spec file, 2.0.0 is the actual version number, and 1.13.2
is the release number.

Hope this helps.

Kris