Re: [PATCH v1 5/7] docs: mark intention to deprecate TCG tracing functionality

Daniel P. Berrangé <berrange(a)redhat.com&gt; writes: > On Wed, May 05, 2021 at 11:41:46AM +0100, Alex Bennée wrote: >> >> Alex Bennée <alex.bennee(a)linaro.org&gt; writes: >> >> > Daniel P. Berrangé <berrange(a)redhat.com&gt; 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.