From: Aaron Patterson <tenderlove@...>
Date: 2012-05-03T02:27:27+09:00
Subject: [ruby-core:44813] Re: [ruby-trunk - Feature #2565] adding hooks for better tracing


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On Wed, May 02, 2012 at 01:01:17PM +0900, SASADA Koichi wrote:
> Hi,
>=20
> (2012/05/02 11:38), Aaron Patterson wrote:
> > DTrace allows us to specify the stability of the probes.  I've
> > declared the provider name of "ruby" to be stable.
>=20
> I agree.
>=20
> > We don't declare any modules or functions, so I've declared them as
> > stable.
>=20
> I'm not sure about it.  You mean that we'll declare "there are no
> modules or functions" ?

That's correct.  We are not allowed to define modules or functions, so
I've declared that our non-existent modules and functions are stable.

> > The probes (e.g. function-entry), as well as the type and number of
> > arguments to the probes are declared as unstable, so users are
> > advised not to depend on them.
>=20
> I agree.  Or declare specification as "Ruby 2.0.0" (specific
> implementation) and make warning that "there are possibilities of
> changing probes after Ruby 2.0.1 or later".

I believe that is implied since we've said the api is not stable.

> > You can find the stability declarations here:
> >=20
> > https://github.com/tenderlove/ruby/blob/probes/probes.d#L26-30
>=20
> Thanks.
>=20
> I have a question:  We have lazy sweep which run many short scattered
> sweep process.  Should we measure such a thing?

I think it's fine to measure.  I've added probes in all the places where
we gather GC statistics (near GC_PROF_SWEEP_TIMER_START and
GC_PROF_SWEEP_TIMER_STOP).  The nice thing is that the DTrace system
will provide the time, so we don't need to write any C code to calculate
timing.

> > I think declaring them unstable is the best conservative approach.
> > If we find them to be good over the long term, we can change the
> > stability declaration in later releases of Ruby.
>=20
> I agree.

Great!  If you're happy with my patch, I'll apply. :-)

--=20
Aaron Patterson
http://tenderlovemaking.com/

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