Saturday, June 20, 2009

Tim Bunce++ !! is one of the great libraries that separates Perl from other dynamic languages. It's my favorite module for determining the performance of code snippets that run external from my full application environment.

Sometimes, you tend to need to know what your response time is at given rates of input, so you can know your boundaries on maintaining a specified level of response time. (A webserver's response time to a dynamically generated request for example). Averages, rates, etc, tend to hide the fat tails on either end of the response time spectrum (of a given rate).

Taking your result set, and looking at from a percentile perspective gives you the fat tails, an idea of what your median execution time is, and it allows you to more easily compare two different rates (say, 100 page requests per second, vs 1000 requests per second).

In my world, it's how many quotes, or orders per second, and every microsecond counts. Finding a fat tail helps us expose design flaws, technical limitations, or simply algorithms that don't scale terribly well.

So, to summarize...

Benchmark is an awesome tool for comparing snippets of code.
Calculating percentiles is a great way to understand how a system is capable of handling varying levels of load, and how "fat" the tails are to understand a systems capacity.

Thursday, June 18, 2009

Why Parrot is important, or not..

Here's the summary that I got from this...

1. Parrot is neat, you can write languages very quickly and easily.
2. Parrot is a register based VM, which is better than a stack based one.
3. Concurrency is hard, Parrot isn't mentioned as being part of the solution, but if we ever figure it out, why not do it in Parrot so we don't have to do it again and again going forward?
4. Parrot is going up against Microsoft's CLR/DLR, and Sun's JVM. Parrot is forcing their hand to make improvements.

I feel like reading between the lines there is a defeatist attitude in the last three paragraphs, that MSFT and ORCL will just hulk smash Parrot with $$ and Parrot is one big academia project that won't end with a system capable of generating production level code. Seriously, that's ok though, they're doing all this for FREE, they don't owe me anything. I'm just thankful for Perl5, my entire livelihood is based on it, and it's an honor to stand on the shoulders of giants to do what I do.

I've been using what little free time I have to try to learn Perl 6 and Parrot (not exactly easy with our first baby arriving a little over a month ago). I'm not sure I want to invest, literally my future into it anymore. Hence my intrigue over Vala. Being a Perl/Java programmer in the past has got me pretty far, but seeing how I hate Java, I'd better find a decent replacement, and I'm not sure Parrot/Perl6 is it.

Vala?! Genie?!

Ok, let me be totally clear. I loathe, and detest java, in all forms. I love Perl. The dynamic nature of scalars, the quick and easy lists and hashes, it's all just too good.. The bonus is "strict" and "fields" that give you that warm fuzzy compiler error, instead of having to hunt issues down with endless unit tests (and even then, you'll probably never find them all)...

But, Perl isn't C++, and well, coding in C++ is about as much fun as pouring gasoline in my eyes. I NEED a language that is faster than Perl, but isn't C or C++, and for the love of god don't tell me about some VM that has magical powers. (I have more to say about Allison's post here in a second).

Sooo, a guy in my office showed me a link to Vala. Wow...

Reference counted memory management..
Braces / semicolons based syntax (or python, if you prefer, use Genie)
Compiles down to a binary (no virtual machine)..
It's only pre-requisite is glib..
Lambda expressions..

Wow wow wow.. So, I give up my untyped scalars, to get C level performance, no more ridiculous XS calls, and I get even tighter compile time safety?! Where do I sign up?