Facebook Rewrites PHP Runtime For Speed

VonGuard writes "Facebook has gotten fed up with the speed of PHP. The company has been working on a skunkworks project to rewrite the PHP runtime, and on Tuesday of this week, they will be announcing the availability of their new PHP runtime as an open source project. The rumor around this began last week when the Facebook team invited some of the core PHP contributors to their campus to discuss some new open source project. I've written up everything I know about this story on the SD Times Blog."

Comments

High performance in scripting languages?

[BadAnalogyGuy]

At some point, if you are lucky enough, you will require extremely high performance from your web pages. You start out coding HTML in Notepad and move on to Perl CGI then on to PHP with scripting embedded right in the generated HTML. All the time you gain programming crutches at the expense of processing speed, and for a while this is a great tradeoff.

But one day you start having server hiccups because your scripts can't keep up with your traffic. Sites like Amazon have already run into this and have moved away from scripting languages and back to system languages. Running applications directly on the CPU instead of relying on a runtime to translate (at best) bytecode into machine instructions means maximizing CPU cycles.

So I wonder what longterm benefit there is in improving the language runtime.

Re:High performance in scripting languages?

[sakdoctor]

1. Static HTML
2. PHP
3. ???
4. Rewrite the PHP runtime

Truth is, that step 3 involves a whole load of steps where 90% of the problem will be database bound. Complied languages are not going to the magic solution in a real world situation.

Three sources of scripting language inefficiency

[tepples]

I don't know what the fascination is with scripting languages on the Linux platform or with FOSS in general, but it results in slow programs

Speed of development is faster in a scripting language, and in developed countries, below a certain scale, throwing hardware at it is cheaper than throwing programmers at it. The point of the article is that Facebook is above that scale, and programmers to write a new PHP interpreter have become cheaper than adding hardware+power+cooling.

with flaky UIs.

Citation needed. True, the often use a different widget set from the rest of the desktop (e.g. Tk from Tcl and Python and Swing from Java), but the popular widget sets also have scripting language bindings. how can one really tell the difference between a wxWidgets or GTK app written with Python vs. C++?

I like to use refurbished/recycled machines; which means that I'll have an old P4, 512M RAM and a slow bus.

Do these use more electric power than, say, an Acer Aspire Revo? The power consumption of a Pentium 4 and the power to remove the heat it generates can become an issue, especially for a server that's turned on 24/7.

Many times, applications written in a scripting language, whether it be Perl, Python, PHP, or whatever, will hang often and then start working.

There are three causes for this, and you can distinguish them with 'top' or 'Task Manager' or something else that can count CPU time and page file accesses:

• Swapping: More dynamic languages tend to use more general data types, which incur memory overhead. For instance, they might use UTF-16 strings instead of 8-bit strings with an assumed encoding. Or they might use double-precision floating point instead of short integers for large arrays. This might cause a program to run out of RAM and fail over to the disk more often.
• Garbage collection: This covers ways of determining which resources are no longer in use by any active part of the program. Python, Objective-C, and lately C++ primarily use an incremental garbage collection method called reference counting, which keeps track of the number of things that "know about" an object. But some other language interpreters use only tracing garbage collection, which in the naive form causes the application to pause and make a list of all live objects once memory allocations exceed some amount. This will cause a CPU spike.
• Blocking: A lot of the APIs available to programs in scripting languages don't have well-known non-blocking versions. For example, a host name lookup might freeze the program until it finishes. The only way to work around these is to start a thread. This will cause a pause with 0 CPU and 0 disk.