Hyper-Threading Speeds Linux

developerWorks writes "The Intel Xeon processor introduces a new technology called Hyper-Threading (HT) that makes a single processor behave like two logical processors. The technology allows the processor to execute multiple threads simultaneously, which can yield significant performance improvement. But, exactly how much improvement can you expect to see? This article gives the results the investigation into the effects of Hyper-Threading (HT) on the Linux SMP kernel. It compares the performance of a Linux SMP kernel that was aware of Hyper-Threading to one that was not." Ah, the joys of high performance.

Comments

It's not possible

[Oculus Habent]

Something that makes your computer run faster also makes free operatings systems faster too?!

I wonder what it does for commercial OSes.

Sorry for the sarcasm, but isn't that obvious? If you have a processor that can do more work than another processor at equivalent MHz, it, by most estimations, will speed something up.

Not true for everything, but pretty close.

This may decrase performance in some cases

[Jack Wagner]

We've been doing some research in the Wagner Labs and we've seen many cases where an app is optimzed for hitting the level II cache and thus reducing the pipeling done by optimizing on modern day compilers and when you use these apps on a hyperthreaded proc you actually see a performance DECREASE by the order of Olog(n) due to the fact that the insctuction set is running parallel in the CPU and never leave the LII cache, thusly never getting a chance of utilizing the advantages of hyperthreading.

Once again this proves the point made by Fred Brooks in "The Mythical Man Month" that even if you increase the technical levels of optimiztion you can will only see actual real-world speed improvements in Olog(n)/4ac, on the average.

That said I do think there is quite a bit of potential for hyperthreading when the compilers are able to catch up, so to speak.

Warmest regards,
--Jack

not to be picky

[DrSkwid]

but surely someone who was qualified to comment would know how to spell kernel?

It's not that I want to pull you up for bad spelling but in order to speak with authority one must get the simple things right.

Apologies if you have some sort of linguistic problem but people who seriously study kernel performance see the word kernel constantly and therefore one would expect them to spell kernel kernel.