As David Soria Parra mentions in a recent post to his blog, the DTrace functionality has been backported to the PHP 5.3 branch and gives developers a bit more information about what's happening inside their applications.

For those not following the PHP development. We backported the DTraces probes from the abandoned PHP 6.0 branch, back to the new trunk PHP 5.3.99-dev. It is called 5.3.99 because the PHP dev community has not decided yet on a version number (5.4 or 6.0).

He gives the configure line to get it working on Solaris and Mac OSX and a sample line of code to ensure everything's working correctly. The results show the full execution of the example. This functionality can replace this extension from the PECL repository.

On the IBuildings techPortal today there's a new podcast posted in the Dutch PHP Conference series - David Soria Parra's talk on analyzing web applications with Dtrace.

DTrace is the Swiss army knife to analyze the behavior of applications and enabling you to gather detailed information from the bottom of your application stack up to the top. DTrace is used by system administrators and developers, on Solaris, Mac OSX and FreeBSD, to do in-depth analysis of an application, to find and reduce performance bottlenecks and problems in productive system. The talk will give an introduction how to use DTrace's capabilities in web development, reflect the current state of DTrace support in PHP and show examples how to trace PHP script in production.

You can listen to this latest episode via their in-page player.

On the Experimentalworks blog a recent post looks at using DTrace, the powerful tool to debug and trace problems in an application, with your PHP applications.

Dtrace is really powerful and trying to do an introduction to all it's features is just not possible. Therefore I will just focus on the basics, that are needed to get our stuff working. The basic idea behind Dtrace is that the kernel and userland programs fire probes on a specific location in the kernel or the userland program.

He looks at the structure of a DTrace program as well as a list of probes that you can use to help track down the problem in your application. His "first example" traces the compile time of the app and, when run on the command line, returns the time in seconds.

After singing the praises of DTrace for a while now, Johannes Schluter decided to show it off in a different way - introducing a collegue to it:

Yesterday, during a break at the Barcamp Munich, I gave Wolfram a short introduction on his Mac and decided to put some stuff here [in this post]. DTrace is a toolkit available on Solaris (Solaris 10 or OpenSolaris), recent MacOS versions and FreeBSD for mightier than tools like truss or strace but with way less impact. DTrace allows you to "hook" (called "probes") into the system and allows to do some analysis then.

He shows how to set up some of these "hooks" using D-script to wrap around a simple PHP script call. He alters the results to show things like the memory function its in, how much of the memory its using and a fun little script that "graphs" out the memory usage with "@" symbols.