To hyper-thread or not to hyper-thread

Greg Woods woods at ucar.edu
Mon Dec 7 16:44:04 UTC 2009


On Mon, 2009-12-07 at 16:18 +0100, Joerg Bergmann wrote:

> 
> The problem of the Pentium 4 D: It is not really a dual core one.
> Hyper-Threading means: There is one core with two execution paths, which
> means some of the common CPU features, but not all, are present twice.

One feature in particular that is not present twice is some of the
caching. This is sort of why they named it "hyperthreading". If you can
get multiple threads of the same process, sharing the same memory, to
run simultaneously, there is a performance boost. But if you try to run
two completely different processes simultaneously, there will actually
be a performance LOSS because of all the cache misses this will cause.

--Greg





More information about the fedora-list mailing list