Page Speed and Webserver Performance

May 22, 2004

At the very bottom of this webpage, you'll see a like that states: "This page was generated in X.XX seconds." This is measured by a little snippet of timing code that we've put into the PHP which generates the pages on our website. Hopefully it's a very small number.

Optimizing your webserver performance is important for high traffic, successful websites. In extreme cases, the user experience is dependant on getting good response from the webserver. Having the webserver take 15 seconds to generate the webpage is generally viewed poorly. On the other end of the spectrum, few users care about the difference between a page genearted in 0.05 seconds and one generated in 0.01 seconds. The Internet lag and their modem/broandband download times are usually much greater than 4 hundredths of a second.

However the difference between 0.05 seconds and 0.01 seconds is also the difference between the webserver processing 20 requests/sec and processing 100 requests/sec. This is much more important to the webmaster/owner of the website. Greater server capacity means that your website can become more successful before having to spend money on faster/more complex hardware.

Optimization Techniques

There are entire books devoted to speed optimization or "tuning" of computer hardware and software, so I really can't into great detail in this one small article, but when you boil it down, most of the easily implemented options are these:

1. Add more RAM - Very often this is the quickest and cheapest method of getting more performance out of your webserver. Consider that 256Mb of RAM now costs less than the server charge most places will sock you for installing it, RAM is pretty cheap, don't skimp on it. As of this writing, I've got 1Gb of RAM on this server.

   RAM is used for two things by your webserver. First and foremost it's used for the programs short-term memory needs. On some systems, any RAM that's left over is used as a disk cache, to store frequently used files from the hard drive. (Linux systems dynamically allocate spare RAM to the disk cache, BSDi systems require the admin to determine how much RAM is used as disk cache when the kernel is compiled. Win2k servers use whatever RAM is left over to act as disk cache.)

2. Index your database tables - Entire chapters of database books are devoted to this subject as the "right" answer varies depending on your situation and how your database tables are used. In general, adding indexes to the table makes database searches faster and database writes slower. Since most data is read many times and written once, it's more efficient to optimize the read operation.
3. Buy a faster server - This suggestion is kind of self-defeating as Justin and I make our living programming, but sometimes it's cheaper and faster to throw newer hardware at the problem. A new low end server can cost as little as $600, which will probably double your server performance, assuming you're replacing a server that's 2-3 years old.

   Professional help (like us) can sometimes achive much greater performance gains, but if doubling is all you need, then new hardware might be your cheapest solution.

4. Code tweaks - Rewriting the code to be more efficient can greatly improve your webserver performance. However this is best left to the pros and will often cost a signifigant portion of the original development costs.

      Rene

If you have any comments or questions, please feel free to drop Rene an email at rene@astutecomputing.com. If you would like assistance in setting up this kind of feature on your website, please contact us for a quote.