Georg Hager's Blog

Random thoughts on High Performance Computing


Fooling the masses – Stunt 15: Play mysterious!

(See the prelude for some general information on what this is all about)

Do you know that feeling when you think to yourself “What on earth did they do there?” when reading a paper? After some depressing hours of trying to figure out how those guys got their results, you just give up, shrug, and cite them in your related work section because everybody else does. “My goodness” you think, “I wish I knew how to do this myself.” Here are some ideas.

Make it as hard as possible for others to figure out what you actually did, so that they can’t compare your results to theirs right away. A popular strategy is to present problem sizes, i.e., the “amount of work,” separately (on a different page) from performance results, which in turn should be given in seconds (time to solution). This will force your audience to figure out the conventional “work/time” performance metric by themselves; many will give up and just believe your statement that you are “faster than X.” It will also be harder to compare with performance models, which is a good thing if you’re off the model by some large factor. Runtime is not the only effective metric; anything unusual will do, such as “microflops per picosecond” or “cache misses per core hour.” Combine with stunt 12 as needed.

Test case problem size
# Iterations Runtime [s]
car see page 4 500  2.34521
plane see page 6 sufficient  3.14159
train see page 2 roughly 112  0.11991
chicken see page 12 whatever  42.0

It’s really useful to be secretive about the exact hardware you were using. “eight-core AMD Opteron” or “six-core Intel Xeon” will usually suffice as a description. You may throw in the clock speed for good measure, but don’t mention whether you have activated Turbo Mode or not, or whether you used one socket or two, or how you enforced affinity. On the other hand, never forget to specify the exact Linux distribution and kernel version! No performance paper will be complete without it. We don’t want to hide anything after all, right?

Talking about openness: leave a good impression by making your software framework available for download. But when you do, take care to make it impossible to actually run it. Forge a totally convoluted, mind-twisting build system. Put in dependencies to several huge Java frameworks with version numbers far into the past or the future (requiring gcc 2.95.2 will work fine, too!). Never write plain C code, always generate it, using popular languages such as Logo, Java2kWhitespace, or Brainfuck (pick any two). Because: what they can’t run, they can’t criticize! (Think “Stupida Mouse!”) Give your software framework a fancy, foreign-sounding name, preferably from a romance language. Acronyms are so 1980s1, but “Inocentada,” “Vanitas,” “Nebulosità,” or “Ordure” will really cut the mustard.

If your strategy works you can even afford to be bold in your abstract: “Our framework achieves up to 34% more performance than previous work.” Since nobody can refute that claim due to your bleeding-edge camouflage tactics, you have laid the foundation of what will be known in a few years as “seminal work.”

1 So I was told by Julian