Holy crap, a full speed dtraceable perl!

brian_d_foy on 2008-01-08T17:27:00

I hope I'm not stealing AndyA's thunder, but this just went by on p5p and I'm excited!

From: Andy Armstrong <andy@hexten.net>
 
I now have a dtraced bleadperl which runs no slower than the clean
version:
 
orig       | dtrace     | ratio
====================================
2.51239896 | 2.47904992 | 0.98672622
2.50696611 | 2.46995783 | 0.98523782
2.52996778 | 2.47554016 | 0.97848683
2.50457382 | 2.47788405 | 0.98934359
2.50622296 | 2.46893001 | 0.98511986
 
In fact in those tests the dtraced version is running marginally
faster. I'm putting that down to a happy code alignment or somesuch.

dtrace is Sun's new thing to allow you to do live tracing of function calls across the entire operating system without having to compile without any special flags and without a performance hit when you're not actively doing a trace. It's been ported to FreeBSD and OS X 10.5.

Unfortunately there's been trouble getting Perl to work with dtrace at the Perl function call level (rather than at the internal C opcode level) without a performance hit. Someone else can answer why, but it appears Andy has solved that problem! They're already discussing the possibility of, if dtrace is available, enabling it by default.

For those who can't wait for bleadperl Andy has Devel::DTrace available on CPAN, though it does have a performance hit.

---

expected

yDNA Barak on 2008-01-09T03:27:55

Part of the point of dtrace is to let one dynamically select what to trace without the performance hit. Or at least things ended up working out that way. dtrace is full of goodness.