Re: [RFC PATCH 00/28] ktap: A lightweight dynamic tracing tool for Linux

From: Ingo Molnar
Date: Fri Apr 04 2014 - 03:36:35 EST



* Jovi Zhangwei <jovi.zhangwei@xxxxxxxxx> wrote:

> On Wed, Apr 2, 2014 at 3:43 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> >
> > * Jovi Zhangwei <jovi.zhangwei@xxxxxxxxx> wrote:
> >
> >> So based on all these input, I suggest:
> >>
> >> Put all these community efforts together, figure out the proper
> >> design implementation of dynamic tracing tool, ktap can be a good
> >> start to build upon it, evolve to a unified kernel script engine
> >> with ebpf together, finally service for dynamic tracing and
> >> network(if possible).
> >>
> >> Our goal is same and very clearly, we really want a "simple &
> >> flexible & safe" dynamic scripting tracing tool for Linux, which
> >> could compare or even better than Dtrace, this is the motivation of
> >> ktap project.
> >>
> >> Two solution may be take:
> >>
> >> 1). upstream ktap into core trace and evolve it step by step, and
> >> finally make a integrated bytecode engine, it's a long process,
> >> but I think it's worth.
> >>
> >> 2). move ktap back into staging, and graduate from staging after the
> >> code make tracing people and ebpf people both happy.
> >>
> >> The benefit is the process will be under the eyes of community.
> >>
> >> Ingo, steven, Greg, what do you think?
> >
> > For now I'm opting for a third option:
> >
> > 3) Maintain my NAK on the ktap patches until they address the
> > fundamental design concerns outlined by Alexei and others in
> > their review feedback:
> >
>
> There is no fundamental design concerns outlined about ktap, [...]

Well, the concerns that were outlined do raise to fundamental in my
book. But as long as they are addressed it does not matter how we
classify them.

> I don't see any suggestion about integrating BPF before this review
> cycle.

Hm, I mentioned it at the kernel summit to folks who raised the ktap
subject, but apparently not over email. I assumed a new ktap
submission would come quickly.

Anyway, considering how BPF is integrating with (and hopefully
replacing) tracing filters, it makes sense to apply the same concept
in the ktap case as well.

Thanks,

Ingo
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