[vtk-developers] Proposal to add "vtkInfoMacro"

Sun Dec 21 17:34:27 EST 2014

Thank you Andras. Happy holidays.

-berk

On Sat, Dec 20, 2014 at 8:57 PM, Andras Lasso <lasso at queensu.ca> wrote:
>
>  Thanks to all for taking time to consider this. I think in the long term
> such functionality should be part of VTK, but I understand if there are
> other priorities now and I don’t want to take more of your time with
> discussing this one particular issue.
>
>
>
> I hope this request will be revisited in the future, please keep it in
> mind when other application support features will be integrated into VTK.
> I’ve entered a ticket to the issue tracker to make sure it will not be
> forgotten: http://vtk.org/Bug/view.php?id=15220.
>
>
>
> Andras
>
>
>
> *From:* Berk Geveci [mailto:berk.geveci at kitware.com]
> *Sent:* Saturday, December 20, 2014 10:49
>
> *To:* Andras Lasso
> *Cc:* David Cole; David Gobbi; Jean-Christophe Fillion-Robin (
> JChris.FillionR at kitware.com); vtk-developers at vtk.org
> *Subject:* Re: [vtk-developers] Proposal to add "vtkInfoMacro"
>
>
>
> I looked at our current structure and could not find a suitable place that
> would allow for non-GUI classes to have access to this but not the core
> classes. It is probably not worth creating a module to just add this header
> so I recommend keeping it in Slicer for now.
>
>
>
> Best,
>
> -berk
>
>
>
>
>
> On Sat, Dec 13, 2014 at 3:42 PM, Andras Lasso <lasso at queensu.ca> wrote:
>
>  You are right, it’s not necessary to make this additional logging macro
> available for core VTK library modules. It can be anywhere in VTK where VTK
> tests, examples, and VTK-based applications can access it. Do you have any
> suggestion for a good place?
>
>
>
> Having the macro in VTK allows a standardization on the macro name,
> parameters, and behavior among all VTK-based applications. The macro would
> be used in application classes derived from vtkObject.
>
>
>
> Andras
>
>
>
> *From:* Berk Geveci [mailto:berk.geveci at kitware.com]
> *Sent:* Saturday, December 13, 2014 15:16
> *To:* Andras Lasso
> *Cc:* David Cole; David Gobbi; Jean-Christophe Fillion-Robin (
> JChris.FillionR at kitware.com); vtk-developers at vtk.org
>
>
> *Subject:* Re: [vtk-developers] Proposal to add "vtkInfoMacro"
>
>
>
> Sorry but I remain unconvinced. I haven't heard a compelling reason why
> this functionality should be available to core VTK modules and why the
> maintainers of those modules need to worry about it. So far, the only
> example is for a class in Slicer.
>
>
>
> Whether this is in a separate header or not, putting it in Common/Core
> will make it possible for all modules in VTK to use this functionality
> without any compile errors. As I mentioned, I'd like to see functionality
> migrate out of Common/Core to outer modules not vice versa. "There are
> other application-only functions in Common already" is not a good reason
> why we should cram more in there. Also, vtkOutputWindow is used for
> VTK-level functionality such as debugging and error reporting. Similar to
> vtkDebugLeaks. I wouldn't call that application specific.
>
>
>
> Best,
>
> -berk
>
>
>
> On Sat, Dec 13, 2014 at 11:35 AM, Andras Lasso <lasso at queensu.ca> wrote:
>
>  Yes, sure we don’t need VTK to include a complete logging framework such
> as log4cpp. We just need a convenient mechanism to send messages to logging
> frameworks from VTK.
>
>
>
> What do you think about the following?
>
>
>
> * Allow completely disable vtkInfoMacro by an #ifdef (for example, if
> #ifndef VTK_INFO_ENABLED then vtkInfoMacro is an empty statement; we can
> set VTK_INFO_ENABLED to false by default)
>
>
>
> * Put the macro in a separate header in Common/vtkInfo.h to not make the
> macro visible to VTK classes by default. GUISupport directory would be too
> restrictive, as logging is not related to GUI and there are other
> application-only functions in Common already (such as
> vtkOutputWindow::DisplayText), but any other suggestion is welcome.
>
>
>
> Andras
>
>
>
> *From:* David Cole [mailto:DLRdave at aol.com]
> *Sent:* Saturday, December 13, 2014 09:28
> *To:* David Gobbi
> *Cc:* Berk Geveci; vtk-developers at vtk.org; Andras Lasso
>
>
> *Subject:* Re: [vtk-developers] Proposal to add "vtkInfoMacro"
>
>
>
> I agree with Berk. VTK should NOT include the kitchen sink... This belongs
> elsewhere -- there are whole separate libraries that are actually focused
> on logging, and doing it in a high performance, high functionality manner.
> log4cpp, g2log, and boost all come to mind.
>
> Great to hear talk of testing performance regressions on the dashboard --
> looking forward to the day that's a reality.
>
>
>
> Thx,
>
> David C.
>
>
>
>
> On Friday, December 12, 2014, David Gobbi <david.gobbi at gmail.com> wrote:
>
>  Well, vtkImageReslice is probably not the best "speed" example any more,
> it has become fat with all the features that I've added to it over the
> years :)   And in the old days, a big reason for its speed was that it did
> some bit-twiddling to work around the disastrously slow floor() operations
> on old CPUs.
>
>
>
> However, it is certainly true with modern computer architectures, with
> their multiple cores and fast caches, doing _any_ application-level or
> system-level operations within the algorithmic code causes a significant
> performance hit, because that takes the CPU core out of the "zone" where it
> can work at its full potential.
>
>
>
>  - David
>
>
>
> On Fri, Dec 12, 2014 at 5:12 PM, Berk Geveci <berk.geveci at kitware.com>
> wrote:
>
>  I'd be fine with it if the header is put into a higher level module such
> as GUISupport and has some examples demonstrating its purpose and some
> documentation providing a guide on how to use it. I would not agree to
> putting this at a place where it may encourage folks to use it in
> algorithms and other core functionality. As I mentioned previously, I
> already have the unpleasant job of ripping out a number of "convenience"
> functionality that are going to have significant impact on performance as
> we continue to multi-thread more algorithms. All of these features look
> harmless when initially added. Then they find their way into core
> functionality slowly but surely. When you are considering 200-way
> parallelism (which we are, since we are porting to Intel Xeon Phi already),
> any little bit makes a difference. Some simple examples:
>
>
>
> * Garbage collection
>
> * vtkDataArrayTemplate::DataChanged()
>
> * Abundant use of Modified()
>
> * Progress reporting
>
>
>
> Very nice and convenient feature. They may lead to a code running more
> slowly as more threads are added rather than scale up.
>
>
>
> I don't agree that misuse of such features would get caught in reviews.
> Very few reviewers are conscious of potential performance issues. Because
> very few developers are performance conscious at this point (Dave Gobbi
> excepted, he writes amazingly fast code, see image reslice).
>
>
>
> So this is not the time to pepper core classes with convenience
> functionality. It is time to simplify and come with very clear guidelines
> on what core classes and algorithms can and cannot do. Once the development
> community becomes more aware of these issues and our dashboards are able to
> catch performance regressions, we can relax some.
>
>
>
> Best,
>
> -berk
>
>
>
>
>
>
>
>
>
> On Fri, Dec 12, 2014 at 9:52 AM, David Gobbi <david.gobbi at gmail.com>
> wrote:
>
>  However, I have reservations about putting this macro in vtkSetGet.h. If
> it goes in its own header, then the chances of it being confused with
> vtkDebugMacro are significantly reduced.
>
>
>
>  - David
>
>
>
>
>
> On Fri, Dec 12, 2014 at 7:24 AM, Andras Lasso <lasso at queensu.ca> wrote:
>
>  I completely agree with David. This is an application support feature.
> There are several examples for such features in VTK, including QVTKWidget
> or vtkOutputWindow::DisplayText(). These are not meant to be used in VTK
> library itself (other than examples and tests) but in VTK-based
> applications. They make the life of application developers easier, allow
> standardization, reduces code/feature duplication.
>
>
>
> Adding the macro has negligible impact on VTK but would help application
> developers.
>
>
>
> Andras
>
>
>
>
>
> *From:* David Gobbi [mailto:david.gobbi at gmail.com <david.gobbi at gmail.com>]
>
> *Sent:* Friday, December 12, 2014 09:16
> *To:* vtk-developers at vtk.org
> *Cc:* Jean-Christophe Fillion-Robin; Berk Geveci; Andras Lasso
> *Subject:* Re: [vtk-developers] Proposal to add "vtkInfoMacro"
>
>
>
> On the one hand, I can see that it is useful to have a message macro that
> doesn't require a debug build.  In my own apps, I often write app-specific
> classes that are derived from vtkObject and this is a macro that I might
> use from time to time.  Unlike Berk, I'm not all that worried that it might
> be abused.  For VTK, we have code review.
>
>
>
> On the other hand, I don't think we have a use case for this within VTK
> itself, it would be there purely to serve external VTK classes and apps.
> And people who need this feature could simply put this macro (or a similar
> one) in their own header files.
>
>
>
> Summary: this is a convenience feature, IMHO a mostly harmless one, and
> one that I might use.
>
>
>
>  - David
>
>
>
>
>
> On Fri, Dec 12, 2014 at 6:27 AM, Berk Geveci <berk.geveci at kitware.com>
> wrote:
>
>  I disagree with this change. There is no compelling VTK specific example
> for why this is needed. The examples are all from Slicer - which to me says
> that they can be implemented in Slicer.
>
>
>
> Adding a logging functionality without clear guidelines on how to use it
> is dangerous. It can lead to folks using it for debugging in performance
> critical sections and since it is not compiled out in Release builds, it
> can lead to significant performance issues, specially in multi-threaded
> code. As it is, there are lot of minor issues like this that we will have
> to go and clean up (progress being one of them).
>
>
>
> The main use case seems to be tracking interaction/workflow changes. My
> suggestion is to employ a method appropriate to that. For example, events
> and listeners.
>
>
>
> Best,
>
> -berk
>
>
>
>
>
> On Thu, Dec 11, 2014 at 12:06 PM, Jean-Christophe Fillion-Robin <
> jchris.fillionr at kitware.com> wrote:
>
>     Hi Folks,
>
> While developing 3D Slicer, we created a macro named
>
>                                           vtkInfoMacro
>
> similar to "vtkErrorMacro/vtkDebugMacro/vtkWarningMacro".
>
> We would like to contribute it back to VTK core.
>
>
>
> The associated topic is:
>
>                       http://review.source.kitware.com/#/c/18385/
>
> It would be great to get feedback before moving forward.
>
> Thanks
>
> Jc
>
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://public.kitware.com/pipermail/vtk-developers/attachments/20141221/becd6a5b/attachment-0001.html>