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What Makes a Valid Benchmark?
An anonymous reader writes "Benchmarks can make a big difference if they are accurate in predicting performance. That's simple enough to describe; it's not nearly so simple to implement. Benchmarks can be an excellent tool for predicting performance and estimating requirements, but they also can be misleading, possibly catastrophically so. This article looks at benchmarks; the good, the bad and the ugly."
are real world apps that your audience will be using.
Interesting, but metrics such as FPS and time to render a frame are equally meaningless for lots of other reasons. For example, you can "cheat" a real-world benchmark by changing the way some routines are drawn. Heck, some graphics cards makers have been known to optimize their code for a particular game or testing routine. A while back some tests would measure the time it took to run a particular Photoshop filters. This was also vulnerable to cheats because you could optimize that particular routine or *specific test* to look good in comparison.
Today we were testing an Oracle data mirror transfer from an older Sun system to a newer pSeries AIX box. The bottleneck first appeared to be the network, then possibly the older Sun's CPUs. After tweaking the system (by spinning off more dmirror processes) we realized that the bottleneck was in fact the newer AIX machine since it was pegging the two CPUs it had. This was reverse to what was the original assumption that the old Sun box was hampering the transfer. Look at the real-world benchmark and it would appear that the Sun machine was slower because that version of dmirror is single-threaded and didn't utilize the other CPUs; thus in an isolated throughput comparison on real data, the AIX machine came out ahead.
What I'm getting at is that no benchmark, synthetic or real-world, is all that useful until you test the actual workload.
This reminds me of a comparison I saw in Circuit City once... (Warning: I'm not going to talk about a computer hardware benchmark.) They were trying to sell the insanely expensive Monster video cables by comparing the Monster cables to standard cables on identical TV's. The screen with the monster cables looks hella better than the other monitor. The difference was so astounding that I just had to look at the back of the TV... The Monster TV was hooked up with an HDMI cable..... The other a FRIGGIN UNSHIELDED COMPOSITE VIDEO CABLE. Apples and oranges, apples and oranges...