Also, I’m not sure why anybody thinks “” is parsed “more” than ”…

Both have escape characters, so PHP has to iterate through the string for each, looking for \\ and \’ in one, and a whole host of things in the other, including, but not limited to: {} $ \” and a bunch of other backslash stuff that I won’t duplicate here when you can rtfm.

Maybe PHP has to go through “twice” for “”, but I sure don’t see why…

It’s still silly to try to optimize where your bottleneck isn’t.

Build it simple/straightforward first, then find bottlenecks and figure out why it’s slow, and ONLY then can you begin to optimize.

@Greg Beaver : Absolutely agree with that.

However, I’d like to point out that you have oversimplified the question of how to load external files and how it affects performance. In Rasmus Lerdorf’s keynote for Drupalcon last year (http://szeged2008.drupalcon.org/program/sessions/rasmus-lerdorf-keynote-simple-hard) he took a simple application and through a series of optimizations, some micro, some more substantial, transformed it from an application that can handle 13 req/sec to one that does 400 req/sec as measured by Apache benchmark.

One of the more significant improvements came simply from changing include_path from “.:/path/to/stuff” to “/path/to/stuff:.” This is certainly a micro-optimization by any definition. Also, by replacing require_once with include, he increased the requests per second (note: not the percentage of execution time, the actual number of requests that can be served per second) by a large percentage.

So, this is all to say, micro-optimizations are sometimes useless, but when you do them in conjunction with a real application, and measure the difference in requests per second, you can get an accurate picture of how much they help, and they can result in several thousands of percentage increase in performance for the application as a whole.

The key is don’t optimize blindly, and consider the tradeoffs that are inherent.

so on the absolute path issue, two things:

a) Did you toy with the realpath cache (and ttl) at all? It helps you somewhat if you jack up the values, etc.. Generally this works well in a production environment when the application only changes with a new deployment.

b) For the “makes code unportable” issue. This is something you can actually take care of in deployment. For example, PEAR has those nifty @foo@ identifiers which can be replaced with a replacement task. So for example, @php_bin@ becomes /whereever/php-cli/is/located. This depends on PEAR’s configuration (which should be taken care of when you set it up/install it).

Nice writing!

Well, on the loop case. I did not said that loop or nested loop isn’t part of programming. I’m just stating the efficiency cost of having too much nested loop. Definitely if you use it right (which is not like 4-10 nested loops) it really doesn’t bother anyone when looking at how powerful computers are nowadays. And in case you know everything. Not EVERYONE does. Furthermore, the link you provided is a bit static, try looking for one that provides a more dynamic result to test on different OS? Nonetheless, its a good references to check it out :)

Single vs Double quote. Well done on spending your time on benchmarking (when there are already real time sites doing it). Anyway, if you really want to do a benchmark on the sentence i wrote, try doing it with a double quote with a variable string embed within it. But this is micro optimization, i believe you won’t be interested with micro optimization.

pre vs post increment. 5% can also mean 0.0000001ms compare to 0.00000001ms. Like you said, it really doesn’t matter.

echo vs print. it really DOESN’T MATTER.

etc….

anyway, I’m just interested with the benchmarking of MICRO OPTIMIZATION and sort of good to know such differences as a programmer although you don’t since it doesn’t provide any benefit to you. But i do agree with you that micro optimization doesn’t help optimize performance big time. May be you odd to read the comment i left on that post before spending the time writing this?