On Thu, 25 Aug 2005, Justin R. Smith wrote: > This is in reply to the people who said this because of > cache-contention. Has anyone benchmarked this? > > There's an article > > http://www.2cpu.com/articles/41_1.html > > that benchmarks hyperthreading in Linux and shows a modest (~29%) > improvement in performance --- depending on applications (with java > showing degradation of performance). Perhaps the linux sheduler does > things differently... In in the last couple of years, I've seen some changes in how we interact with HTT. 2-3 years ago, when benchmarking MySQL with and without HTT, I saw a 30%+ drop-off when HTT was enabled. Now, they come out about the same. I previously also saw no improvement with buildkernel, but recently I've seen credible reports of build improvements when running with HTT. So I think that things have changed a bit as a result of significant scheduler improvements in the last few years, as well as reduced lock contention. A continued slight decrease in performance for some benchmarks wouldn't surprise me, but seeing more in the way of "break even" or even "improvement" strikes me as likely. A thorough revisiting of the issue would be quite useful :-). Robert N M WatsonReceived on Thu Aug 25 2005 - 14:37:13 UTC
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