Messages in this thread | | | From | Alexei Starovoitov <> | Date | Wed, 4 Sep 2019 08:51:21 -0700 | Subject | Re: [PATCH 2/2] sched/debug: add sched_update_nr_running tracepoint |
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On Wed, Sep 4, 2019 at 8:40 AM Joel Fernandes <joel@joelfernandes.org> wrote: > > On Wed, Sep 04, 2019 at 08:25:27AM -0700, Alexei Starovoitov wrote: > > On Wed, Sep 4, 2019 at 6:10 AM Joel Fernandes <joel@joelfernandes.org> wrote: > > > > > > I wonder if this distinction of "tracepoint" being non-ABI can be documented > > > somewhere. I would be happy to do that if there is a place for the same. I > > > really want some general "policy" in the kernel on where we draw a line in > > > the sand with respect to tracepoints and ABI :). > > > > It's been discussed millions times. tracepoints are not abi. > > Example: android folks started abusing tracepoints inside bpf core > > and we _deleted_ them. > > This is news to me, which ones?
those that your android teammates abused!
> > Same thing can be done with _any_ tracepoint. > > Do not abuse them and stop the fud about abi. > > I don't know what FUD you are referring to. At least it is not coming from > me. This thread is dealing with the issue about ABI specifically, I jumped in > just now. As I was saying earlier, I don't have a strong opinion about this. > I just want to know what is the agreed upon approach so that we can stick to > it. > > It sounds like the agreement here is tracepoints can be added and used > without ABI guarantees, however the same is not true with trace events. > Where's the FUD in that?
Anything in tracing can be deleted. Tracing is about debugging and introspection. When underlying kernel code changes the introspection points change as well.
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