Why Is Performance Important?

If you have ever sat waiting for a computer to do something, (while pounding on your desk, cursing, and wondering, "What is taking so long?"), you know why it is important to have a fast and well- tuned computer system. Although not all performance problems can be easily solved , understanding why things are slow can mean the difference between fixing the problem in software, upgrading the slow hardware, or simply throwing the whole computer out the window. Fortunately, most operating systems, Linux in particular, provide the tools to figure out why the machine runs slowly. By using a few basic tools, you can determine where the system is slowing down and fix the parts that are running inefficiently.

Although a slow system is particularly annoying to end users, application developers have an even more important reason to performance tune their applications: An efficient application runs on more systems. If you write sluggish applications that need a zippy computer, you eliminate customers who have slower computers. After all, not everyone has the latest hardware. A well-tuned application is usable by more customers, resulting in a bigger potential user base. In addition, if potential customers must choose between two different applications with similar functionality, they often choose the one that runs faster or is more efficient. Finally, a long-lived application likely goes through several rounds of optimization to cope with different customer demands, so it is crucial to know how to track down performance problems.

If you are a system administrator, you have a responsibility to the users of the system to make sure that it runs at an adequate performance level. If the system runs slowly, users complain. If you can determine the problem and fix it quickly, they stop complaining. As a bonus, if you can solve their problem by tuning the application or operating system (and thus keep them from having to buy new hardware), you make company bean counters happy. Knowing how to effectively use performance tools can mean the difference between spending days or spending hours on a performance problem.

Linux: Strengths and Weakness

If you use Linux, maintain it, and develop on it, you are in a strange but good situation. You have unprecedented access to source code, developers, and mailing lists, which often document design decisions years after they are made. Linux is an excellent environment in which to find and fix performance problems. This contrasts a proprietary environment, where it can be difficult to get direct access to software developers, may be hard to find written discussions about most design decisions, and is nearly impossible to access source code. In addition to this productive environment, Linux also has powerful performance tools that enable you to find and fix performance problems. These tools rival their proprietary counterparts.

Even with these impressive benefits, the Linux ecosystem still has challenges to overcome . Linux performance tools are scattered everywhere. Different groups with different aims develop the tools, and as a result, the tools are not necessarily in a centralized location. Some tools are included in standard Linux distributions, such as Red Hat, SUSE, and Debian; others are scattered throughout the Internet. If you're trying to solve a performance problem, you first have to know that the tools you need exist, and then figure out where to find them. Because no single Linux performance tool solves every type of performance problem, you also must figure out how to use them jointly to determine what is broken. This can be a bit of an art, but becomes easier with experience. Although most of the general strategies can be documented, Linux does not have any guide that tells you how to aggregate performance tools to actually solve a problem. Most of the tools or subsystems have information about tuning the particular subsystem, but not how to use them with other tools. Many performance problems span several areas of the system, and unless you know how to use the tools collectively, you will not be able the fix the problem.