<snip>
For example, foreach($aHash as $val) has script execution time of 558% compared to while(list($key) = each($aHash)) $tmp[] = $aHash[$key] with 100%.
</snip>

That is not what is on Vincent’s site … in fact it says exactly the opposite … this is two teenagers w4nking each other off … expert php programmers my expert a$$

Need to do a massive sort when massaging data, without having ORDER BY put a temp table on disk, relatively tight memory conditions with dozens of requests-per-second and C/C++ isn’t a good fit because of platform interoperability? Profiling can find the bottlenecks, but its lists like this that’ll give you some options to try when foreach copies your array. The same ideas applies to using Yslow, EXPLAINing queries, checking the slow query log, etc., etc., etc. Best practices come from some reading and lots and lots of practice, or to quote Niels Bohr: “An expert is a person who has made all the mistakes that can be made in a very narrow field.”

Not to be intruding or anything…. but if you actually read everything on phpbench.com, including the item down the bottom, you’ll notice that I indeed know clearly all that has been said within this page. The intent of showing off these benchmarks was not whatsoever the purpose of this page.

I am no expert at what I do, but I put most of my time into algorithms, mysql benchmarking and server optimisation as any php expert should. Please don’t lecture people how the “right” way of doing things without understanding the correct situation, instead, please just put your ideas on the table and discuss this through like the responsible people you are.

I’d continue but I think that’s all that needs to said.

First off the results are horribly wrong for most of the tests, not to mention the most efficient solutions are in many of the cases not even there.

The author (Chris) also does not seem to understand why the tests “vary”. Performance benchmarks of this type must always be run in an confined enviroment with no unnecessarily processes running. Running them on a shared hosting account, is a clear sign that he dont know what hes doing.

I also strongly recommend that you read up on the differences between php4 and php5 Chris.

To be honest I had expected better from a SitePoint article, this place is starting to provide articles in similar quality as those you find in gossip magazines. It is articles like this one that is the reason that there is 99 bad PHP developers for each good one.

As others has mentioned above, pre-optimicing is the source of all evil. Dont give away code readability for optimicing its not even sure you need. In most cases, easy readable code is also the most efficient. Though, every developer has their own “version” of what is easily readable code ;)

By the way, am I the only one appalled that SitePoint (who I really like and depend upon for accurate commentary) blundered so badly on this article? It seems as if nearly everyone who ran the benchmarks themselves found just the opposite of the authors, and a simple peer review might have avoided that embarrassment.

My compliments and appreciation to metapundit for expressing all of those thoughts.

Dorsey

That’s a little inflammatory so let me get a few things out of the way. I’m not knocking Chris Vincent - I’ve never heard of him and I’m willing to stipulate sight unseen that he is a better programmer than I. Same goes with Akash Mehta - I’ve got no grudge against personalities and I’ll happily say he probably has better programming chops than I do… Lot’s of people do!

That out of the way: stop mentioning this crap!

Look - 99% of PHP programmers will never be in a situation where the CPU performance of their code is important. “Slow” applications are network bound, and database bound most of the time and increasing the runtime of your PHP code does not matter! If your web app is running slowly, you can make it run faster by learning to generating less HTTP requests and making fewer datastorage calls (Database or filesystem). Seriously - this is standard wisdom and it cuts across web development platforms (same advice applies to Ruby, Perl, Python, etc). If you are in the 1% (say you’re writing a pure PHP bignum library: performance comes from data structures and algorithms. Don’t make microbenchmark changes unless you’ve profiled and proven that they are necessary!)

Think about it - why would we care about these benchmarks? Because we want our code to run faster right? Well no - I only want my code to run faster if it’s not running fast enough right now! If it takes .005 seconds to generate a page and the average user takes 1-5 seconds to load it across the network going through my code to gain even a dramatic 100% speedup (more on that in a second) won’t change the user experience at all!

So you say - I’m in the 1%! I need to speed up my app! I have a server load in double digits, pages take 30 seconds to render due to CPU load… I gotta have faster running code! Again - refer to above. It is the accepted wisdom of web dev’s across languages that the fault is probably not based on micro benchmarks (whether you used while loops or for loops). Check your database indexes and profile all the sql calls you’re making. Having the right indexes can change the BigO quality of your queries… And lastly check out caching. Do you really have to calculate every piece of data every time? Memcache is lightning fast and even going to a filesystem Cache system like PEAR’s Cache_Lite can dramatically affect performance. Which is better: making your 1000 line’s of code run 25% faster at the expense of less readable code or not running the code at all 9 times out of 10 and simply serving out of the cache? (Hint: 1000% > 25%).

Ok - enough ranting about what you should do (ie actual best practices) - here’s why you don’t care about the micro-benchmarks unless you actually work on the PHP runtime itself. You visit PHPBenchmark.com and see: hey I can speed up my 31% by using double quotes to assign strings rather than single quotes! I should go back through all my old code and make replacements!

No you shouldn’t. Single quotes and double quotes mean different things in PHP. Single quotes means No interpolation! If I see a line like

it tells me that you won’t have special characters like \n, you won’t be using $var in the string somewhere. It means something. And no you won’t get a 31% speedup - how many lines in your 1000 line codebase are string assignments? 5%? Great you just made 50 changes to get a 1.5% speedup. And of course you used a search and replace and didn’t realise that one of those strings contained a $ sign so now you introduced a bug. Oh and in the next point release of the PHP runtime the performance characteristics of the language change and your performance gains are gone.

Get the picture? Language features like foreach($var as $k=>$v) exist because they communicate your intent more precisely and concisely and that is what you should care about as a programmer. Well written program logically structured with clear code? Easy to optimise. Ball of mud with liberal use of microbenchmark best practices? Good luck… Programming is writing for people first (you if nobody else) and computers secondly. CPU time is cheap, programmer time is expensive.

My rant is running out of steam. Let me address Chris and Akash. Chris first - your site is valuable to two groups of people. Yourself (because writing code and completing projects is good for programmers) and the PHP language developers. The only people who should look at micro-benchmarks are the core devs who should be making foreach as fast as while and should be making single quotes as fast as double quotes. For everybody else - this stuff is bikeshedding at best and counterproductive to the inexperienced who don’t know better (think about it - beginners read this stuff and don’t even know if they have an opcode cache or not). Seriously - put up a big disclaimer at the top of the page directing people looking to make their code run faster to the Wikipedia page on Big O notation. Or at least direct them to useful optimization advice like http://phplens.com/lens/php-book/optimizing-debugging-php.php

And Akash - you write a fine article. But if you want to talk about optimization do the PHP world a favor and write about algorithms, caching options, server (Apache, MySQL) tuning and so on. Teaching people how to run a profiler and actually find out where their code is slow would be useful. If on the other hand you want to write about how to code please don’t add to the stream of advice that misses the forest for the trees. Only one of the links you posted was that useful. People write “637 ways to speed up your code” style posts because they’re easy! Don’t do easy (and trivial, transient, and useless)- do hard. Do algorithm analysis. Talk about database performance. Look YSlow’s list for optimizing the client side. My intent isn’t to be mean to anybody and I know it’s fun to look at the numbers. Geeks like to argue over minutia. So be it. But don’t pretend that it is important or “best practice” and don’t confuse newbies who might think that they should pay attention to this stuff…

But the idea is neat and hopefully the code will be updated.

In one example, a global array variable is set with the name $aHash. The following functions, however, operate on a nonexistent global variable named $x instead. Needless to say the resulting numbers seem quite surprising if you are not aware of the error.

In some cases results appear so far off it leads me to wonder if the site may be mishandling exponents by stripping off the “E” at the end, considerably multiplying the actual value. e.g. treating 5.004E-5 as 5.004

As the previous posters who also took the time to run some of these tests have noted, the site’s results do not square.

Even if a tiny details like foreach instead of while loop doesn’t change alot a page speed, after one month, it is saving alot. So imagine all those tiny details, at the end, change alot in terms of optimisation.

I am doing some MySQL test these days and I see things with a table of 2 million rows that I do not see with a smaller table. So even if it seem like a waste of time, you end up by learning new technique that you’ll replicate in the future.

Why some people hate so much Flash website….. exactly because ’seasoned programmer’ code very bad! So telling that it is not important prove the level of professionalism of some people!