Hyperthreading and SMP

Kenneth Porter shiva at sewingwitch.com
Mon Jan 3 12:58:18 CST 2005

--On Monday, January 03, 2005 1:15 PM -0500 Kuba Ober 
<kuba at mareimbrium.org> wrote:

> I suspect that something else is going on that probably has little to do
> with  wine but a lot to do with that application's memory access
> patterns.  Hyperthreading has known cases in which if memory is the
> contention source,  running two threads on same physical CPU but separate
> logical ones will slow  things down.

Thanks, I'll have to see if I can find out more about that so I can pass it 
upstream to the app's devs.

> Since wine is a multi-process thingo, probably the application process
> and  wineserver have been thrasing that single CPU's caches by trying to
> run  concurrently on two logical CPUs. If you have SMP HT machine, it'd
> be safest  methinks to run the app locked to one logical CPU on given
> physical CPU, and  the wineserver on either the same logical CPU or on a
> different physical CPU.
> I hope I make sense :)

Yep, given your first paragraph. Thanks for the details.

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