is dual core = multi processor?

  • Thread starter Thread starter Cartoper
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Cartoper

I am a software developer working on a program in which I am about to
introduce threads. The more the processors, the better. In years
past I learned the hard way that running on a hyperthreaded box verse
a true multithreaded box gives you very different results, at times.
Am I going to get yet a thrid type of results from running on a dual
core machines or is it really the same things, for my purposes, as a
multi threaded box?
 
Cartoper said:
I am a software developer working on a program in which I am about to
introduce threads. The more the processors, the better. In years
past I learned the hard way that running on a hyperthreaded box verse
a true multithreaded box gives you very different results, at times.
Am I going to get yet a thrid type of results from running on a dual
core machines or is it really the same things, for my purposes, as a
multi threaded box?
Click to expand...

Dual core is 2 separate cores. They may or may not be on the same die -
multiprocessor as opposed to multi-core, but they are 2 CPUs with their own
cache and pipeline. Hyperthreading is a technology that uses the idle cycles
of a processor to create a virtual CPU. it will appear as 2 processors, but
can only run 1 thread at a time. With multi-core / multi-processor you are
going to need critical sections and deadlock handling.
 
I am a software developer working on a program in which I am about to
introduce threads. The more the processors, the better. In years
past I learned the hard way that running on a hyperthreaded box verse
a true multithreaded box gives you very different results, at times.
Am I going to get yet a thrid type of results from running on a dual
core machines or is it really the same things, for my purposes, as a
multi threaded box?
Click to expand...


Yes, dual core (AKA Core2Duo or Athlon X2?) is really two
processors fully capable of using two threads independently
as if it were two discrete processor *modules*.
 
In message <[email protected]> kony
Yes, dual core (AKA Core2Duo or Athlon X2?) is really two
processors fully capable of using two threads independently
as if it were two discrete processor *modules*.
Click to expand...

And better, AMD's crossbar technology allows the cores to communicate
directly, so caching tends to be more efficient on a dual-core rather
then dual-CPU implementation (assuming total cache sizes are the same)
 
Somewhere on the interweb "DevilsPGD" typed:
In message <[email protected]> kony


And better, AMD's crossbar technology allows the cores to communicate
directly, so caching tends to be more efficient on a dual-core rather
then dual-CPU implementation (assuming total cache sizes are the same)
Click to expand...

Whereas Intel's Core2 Duo/Quads have shared L2 cache so that either/any core
can access data in the cache instead of having to load it into a discrete
cache first a'la AMD. <g>
 
In message <[email protected]> "~misfit~"
Whereas Intel's Core2 Duo/Quads have shared L2 cache so that either/any core
can access data in the cache instead of having to load it into a discrete
cache first a'la AMD. <g>
Click to expand...

AMD did it first though, which is why I used them as an example.
Pentium-Ds of the same era fell back to FSB speeds to move data between
the CPUs, whereas AMD CPUs were doing it at CPU speed.

Intel did it better. That's often been the case.
 
Somewhere on the interweb "DevilsPGD" typed:
In message <[email protected]> "~misfit~"


AMD did it first though, which is why I used them as an example.
Pentium-Ds of the same era fell back to FSB speeds to move data
between the CPUs, whereas AMD CPUs were doing it at CPU speed.

Intel did it better. That's often been the case.
Click to expand...

Ahhh, okay, thanks for that. I'd deliberately avoided reading about
dual-core CPUs until recently as I didn't want to tease myself with what I
couldn't afford.

However, after selling my old Barton and nForce2 Ultra mobo on <local
version of eBay> and buying a mobo that allowed me to use my existing DDR
RAM and AGP card I've just "got into the scene" so to speak. Running an
E4500 on a "1066" FSB for 2.93 GHz. :-)
 
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