Chapter 32. Performance Tuning

IN THIS CHAPTER

• Optimizing Services

• Using PowerTweak

• Tuning Hard Disk Drives

Squeezing extra performance out of your hardware might sound like a pointless task, given how inexpensive hard drives and memory have become over time. To a certain degree this is true, for most folks at least. But as we've said before, Linux users are tinkerers at heart. Many of us will gladly spend hours to make our computers work harder, faster, and smarter. Like the amateur auto mechanics of generations past, a cottage industry of overclockers and performance zealots has risen among the hordes of geekdom. And with the capability that Linux and other open-source software gives you to look under the hood and see for yourself what's going on, you can find the way to squeeze that last bit of juice out of an application.

The amount of benefit you can get by optimizing your system varies, depending on what kinds of tasks you are trying to perform. Even with all the shortcuts built in to any modern word processor, no software tricks will make your fingers type any faster in OpenOffice.org under SUSE Linux than in Microsoft Word in Windows. In the next few pages, we will look at ways to get a little more oomph out of your SUSE Linux system.

You should understand that optimization is not an absolute term. You can do almost anything to improve performance for a computer or specific application, and still have room to get even more out of it. But after a while, the law of diminishing returns starts kicking in, and you start working too hard to get not much back. So use these tips and methods, but remember that the reason you want to improve your performance is not for its own sake. You want to get some work done, too.

Nowhere else is the auto mechanic metaphor more appropriate than among the folks who muck around at the lowest levels of their systems. These are the folks who break down specification lists and performance metrics and consider them all a challenge to get more out of them than they were promised. This section is for these folks.

Before you undertake any of this type of work with Linux, keep a couple things in mind. First, perform a benchmark on your system before you start tweaking it. A good package to use for this task is hdbench, available from http://www.hdbench.net. Another good benchmarking tool is bonnie. The bonnie utility is available on your SUSE Linux CDs.

Many other packages are available as well. If you visit http://www.freshmeat.net, you can search for the term "benchmark" and find a variety of packages. If you happen to be a programmer, you can probably develop your own benchmarking tests, and perhaps you want to offer those to the Linux community after they've been tested a few times on your own system.

Second, tweak one thing at a time. If something bad happens (and tweaking is all about finding the limits, after all), make it something that's easy to trace. Log in your book what works, what doesn't work, and what breaks. Then move on to the next thing.

If you're going to find the limits of your system, have two things ready at all times: a good backup of your important data and the batch of six boot floppy disks to rescue your system if you need to. If you haven't yet, go to the YaST System page and launch the Create a Boot, Rescue, or Module Floppy module to perform this absolutely essential task.

Let's begin by discussing how to optimize the services running on your system.