Re: Good, free profiling?

> Do you have any thoughts on whether the Global object should be included
in
> 2.3 or 2.4?

2.4

2.4 is not that far off, given the head start we have on it.  I'd rather we
put 2.3 to bed as soon as possible.

>
> regards Malcolm
>
> >From: "Howard M. Lewis Ship" <[email protected]>
> >To: "Tapestry Contrib" <tapestry-contrib-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
> >Subject: [Tapestry-contrib] Good, free profiling?
> >Date: Wed, 1 Jan 2003 23:03:24 -0500
> >
> >Is there a good, free (and/or open source) profiling tool?
> >
> >Tapestry 2.4 performance may be slipping a little; I can't tell because I
> >don't have access to any profiling tools.  Luis Neves has previously
> >commented that the bottleneck he observes is in character-to-byte
> >conversions, deep inside java.io.  I'm now concerned that all the cool
2.4
> >features such as dynamic page and component discovery are also eating up
> >too
> >many cycles (especially when a page is first loaded).  Also, I'm getting
> >concerned about inneficient threading, since there are more chunks of
> >Tapestry that must be synchronized.
> >
> >The new page persistance stuff is working well, though its a bit more
picky
> >about what types of objects are allowed as persitent properties.  Each
> >persistant page property is now stored individually in the HttpSession.
> >The
> >engine now only stores a list of pages with persistent properties.
> >
> >The basic types, such as String, Number, Boolean work fine.  It
> >differentiates between mutable and immutable objects.  Immutable objects
> >are
> >String, Number, Boolean, java.util.Date (which is slightly fudging), Enum
> >and anything marked as IImmutable (a new marker interface for immutable
> >objects).
> >
> >Mutable objects are tougher since the persistance wants to keep an
isolated
> >copy of properties.  That is, fireObservedChange() results in a copy
being
> >made, and when a page is rolled back in a later request cycle, a copy (of
> >the copy) is made.
> >
> >It's less efficient, but it means no surprises, especially in a clustered
> >environment.  It forces the user to be careful about setting values, you
> >must follow a get/modify/set pattern, no fudging.  It's also going to
help
> >with some timing issues that occur when multiple requests against the
same
> >engine run concurrently ... triggered by frames, but also by private
> >assets.
> >
> >The problem is handling the copying of values.  At best, its going to do
a
> >shallow copy.  As a last resort, Serializable objects are serialized and
> >deserialzed (to make a deep copy).
> >
> >Individual classes or interfaces need their own handler (IValueCopier)
> >registered with a IValuePersister.  The good news is this provides a
clean
> >way to handle things like EJBObject (which is now converted to an
> >EJBObjectWrapper, which implements Serializable to read and write the
> >object's handle).
> >
> >However, for mutable objects like List, a specific handler must be
created,
> >i.e.:
> >
> >public class ListCopier implements IValueCopier
> >{
> >     public Object makeCopyOfValue(Object value)
> >     {
> >         List list = (List)value;
> >         return new ArrayList(list);
> >     }
> >}
> >
> >I think this is the right course to pursue, but I'm concerned that the
> >framework will get finicky.
> >
> >Status: 22,440 NCLOC, 70.5% coverage
> >
> >----
> >Howard Lewis Ship
> >[email protected]
> >http://tapestry.sf.net
> >
> >
> >
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