3 ms·
Performance per watt depends on the computer and the workload. It's not apparent from the SPECint benchmarks they show in the article, but chips like Atom are b
by pjscott 16y ago
Performance per watt depends on the computer and the workload. It's not apparent from the SPECint benchmarks they show in the article, but chips like Atom are better than beefy server chips for some server workloads, and worse for others, when measuring performance per watt. Here's a paper from Berkeley's RAD lab which tries two Atom processors and a Xeon on several different server workloads, and compares their performance per watt:
http://www.sigops.org/sosp/sosp09/papers/hotpower_10_chun.pdf http://www.sigops.org/sosp/sosp09/papers/hotpower_10_chun.pd...
The tl;dr version is that what you really want are hybrid datacenters, where you can assign various workloads to different types of machines, and use each machine type for what it's best suited to do.
- ssp 16y agoSee also this: http://www.realworldtech.com/page.cfm?ArticleID=RWT090909050230 http://www.realworldtech.com/page.cfm?ArticleID=RWT090909050... for a comparison of various types of chips.
- pjscott 16y agoThat chart compares theoretical peak GFLOPS per watt, which is an absolutely terrible metric for server workloads. As the paper I linked to showed, Atom is sometimes much better and sometimes much worse than large, fast server processors in performance per watt on real server workloads. Those charts don't take into account things like cache, or branch prediction, or multicore memory coherence. The only way to get meaningful performance per watt data is to actually run real workloads on various processors.
- ericd 16y agoYeah, there are still some single-threaded tasks that I want my servers to be able to tear through. For serving up HTTP requests, though, this sounds great.