[Python-Dev] Python profiler and other tools

[Alexander Belopolsky]

On Sun, Jul 25, 2010 at 1:22 PM, "Martin v. Löwis" <martin at v.loewis.de> wrote:
..
> It is at best entertaining to ponder about reasons here; I doubt
> anything productive can come out of such a discussion.
>

I disagree.  Depending on the reasons for the relative lack of
attention to these components, several alternative actions can be
taken to improve the situation.   Let's focus on the trace module
because it is the simplest and in my opinion the most neglected of the
three.   Guido suggested that a tool like this is best developed
outside of stdlib and python-dev should focus on providing stable
interfaces such as sys.settrace to third party projects.   On one
hand, I would agree that it is better not to distribute the trace
module at all than to distribute a broken implementation.   (Quality
of coverage tools is particularly important now when many developers
try to improve up their test coverage before or during transition to
3.x.)  On the other hand, using sys.settrace interface requires
knowledge of the frame object structure which AFAICT is an
implementation detail and may change from version to version.  I think
stdlib should expose a more abstract tracing API such as one
implemented by the trace module which would hide frame object details
from the user and give direct access to the data extracted from the
frames such as file names and line numbers.  A higher level module
within stdlib can take advantage of implementation details and not be
burdened by having to support multiple releases as long as its own
user facing API is stable.

> It may be fun posting a message to a ten-year-old issue saying
> "ACT NOW (you sluggards)", but I question that this will, on average,
> improve things. Likewise, speculating that tool support is deliberately
> ignored probably won't improve things (specifically *not* responding
> to Nick here).
>

I assume this is directed at Mark Lawrence even though I made the top
post under this subject.   While I expressed my own share of criticism
of Mark's ways,  I do believe that what he is doing is extremely
valuable.   I did not expect such an outcome, but Mark had a lot of
success closing the issues that simply slipped under the radar, but
were resolved or close to resolution in every other respect.   He is
apparently putting a lot of his volunteer hours into this work and
this is reason enough to overlook occasional rants or poor choice of
words.  Mark's breadth-first approach to the tracker is unique and
does not work for a lot of issues, but at the same time it does work
maybe 10-20% of the time and as long as Mark himself does not get
discouraged by the low success rate and learns how to communicate more
effectively, I think his work will continue benefiting python.

> On the other hand, posting actual patches that fix actual bugs can
> make a lot of a difference. Also, having a maintainer who is willing
> to look into these patches and accept the good ones will make a lot
> of a difference.

With respect to the trace module, I started both of these things
already, but I would really like to hear feedback from people
interested in the future of pdb and profile modules as well.