Performance is still a feature

The recent Linux plumbers conference included a session on getting Linux to boot in 5 seconds (see also the write-up here). It was great to see the report, because performance gets far too little attention. Most of the business world runs Windows rather than Linux, at least on the desktop, and in most respects Windows seems slower than Linux on the same hardware. I would give anything to have Vista boot in 5 seconds on my laptop. In fact, the main problem with Windows Vista is not driver compatibility, or annoying security prompts; it's that little spinning bagel that appears only too often. When I start Microsoft Outlook 2007, I brace myself for an extended pause while it starts up, during which the whole system becomes unresponsive. By contrast, I still enjoy using an ancient version of Paint Shop Pro for working with images, even though I have Adobe PhotoShop installed, because it starts in a blink and does exactly what I need.

The old joke is that what Intel giveth, Microsoft taketh away; but it is not a joke any more. Time spent waiting while a computer boots, or reboots to apply an update, or sits there doing who-knows-what in one of those sulky pauses, is time when we could be getting on with our work. Those delays cost real money, every day. They are also aggravating, sometimes not only for the immediate user. If I am on the telephone, for example, Outlook's slowness is not only a problem for me, but also for someone else trying to arrange a meeting.

I suspect that Microsoft made two wrong assumptions. First, that hardware improvements would remove performance issues. Fast hardware does mitigates problems, but really only disguises rather than fixes slow code. Further, the popularity of mini-laptops and other low-power devices means that fast hardware cannot be assumed. Second, Microsoft intended Vista to be always on, relying on sleep and resume instead of fast start-up. Unfortunately sleep and resume tends to be unreliable, and many Windows updates still require a system restart.

The same factors apply to web sites and web applications. One of the things that keeps people going back to Google is the consistently excellent performance of its site, especially in search. I am convinced that this has a subliminal impact, and that we instinctively prefer the sites that are more responsive. PHP inventor Rasmus Lerdorf speaks frequently about performance - last August at Drupalcon, for example - and is intolerant of slow applications; it would be great if more industry leaders shared his attitude.

There is little we can do about Windows boot times - well, apart from happy hours spent messing with msconfig, the System Configuration Utility - but that does not apply to our own development work. A project is not really done until the performance is satisfactory, even if all the other features work as specified. Performance is easy to measure, and there are plenty of profiling tools that show up bottlenecks in the code; tools like Rational PurifyPlus, Intel's VTune, or for .NET Redgate ANTS; there are also free tools available. The trick is to focus attention on what is too slow, rather than wasting time on what is already fast enough. It is rewarding work, since applications that perform well are a delight to use. Performance goes hand-in-hand with design, about which I posted a couple of weeks ago; they are both essential parts of the user experience, and a good user experience means a high level of satisfaction. There's nothing better for keeping customers coming back for more.