On Mon, May 17, 2021 at 11:47:11AM +0100, Alex Bennée wrote:
Daniel P. Berrangé <berrange@redhat.com> writes:
On Wed, May 05, 2021 at 11:41:46AM +0100, Alex Bennée wrote:
Alex Bennée <alex.bennee@linaro.org> writes:
Daniel P. Berrangé <berrange@redhat.com> writes:
On Wed, May 05, 2021 at 10:22:57AM +0100, Alex Bennée wrote: <snip>
+TCG introspection features +-------------------------- + +TCG trace-events (since 6.1) +'''''''''''''''''''''''''''' + +The ability to add new TCG trace points has bit rotted and as the
When you say this "has bit rotted", just how bad is the situation ?
Is the TCG tracing still usable at all, or is is fully broken already ?
Well patches 6/7 got it working for generic TCG things. I haven't been able to get the architecture one working but I suspect that is some sort of interaction between the per-arch trace header generation that I haven't quite figured out yet.
Ahh it's since 7609ffb919 (trace: fix tcg tracing build breakage) which limited tcg/vcpu events to the root trace-events file.
That commit is from release 2.10.0.
The other commit mentioned in patch 6 (73ff061032) is from 2.12.0.
So no one has been able to use this feature for 3+ years already.
Is it actually worth fixing and then deprecating for 2 releases before deleting, as opposed to just deleting the broken code today on basis that it can't have any current users ?
Well I can get it up and running with the aforementioned patches and it seems reasonable to give some notice. I'm happy to defer to Stefan here though as it's his sub-system.
Lluís Vilanova was the author and probably main user. He mentioned he's been away from QEMU for a while. If you want to drop the feature, I think that's fine since it has already been broken for over 3 years. If someone wants it back then it can be added via TCG plugins in the future. Stefan