Re: Good, free profiling?

Hi Howard,

I don't know of any free profiling tool. I have found JProbe is a great 
tool. I think someone once said we should pool some dollars to buy this for 
you/Tapestry, I can kick in some Aussie dollars (for what they are worth).

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

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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