[petsc-users] Understanding the memory bandwidth

Satish Balay balay at mcs.anl.gov
Thu Aug 13 15:40:55 CDT 2015

On Thu, 13 Aug 2015, Matthew Knepley wrote:

> > Also, can someone elaborate on the difference between the words
> > "core", "processor", and "thread"?
> >
>  A core and a processor are hardware terms. I think they are both
> fuzzy, but I understand a core to be something that can carry a
> thread of execution, namely a program counter, instruction and data
> stream, and compute something.  A thread is a logical construct for
> talking about an execution stream.

Perhaps there are multiple terminologies here - but I think you are
asking about the difference between:

CPU/processor, core, hardware-thread

CPU: a (manufacturing) packaging unit. Or a single chip that can be
inserted on the MotherBoard.

Core: a CPU can have multiple cores. Each core is equivalent to
independent processing unit

hardware-thread. Its a virtual mode for a single core (hardware)
process multiple streams of instructions simultaneously (aka virtual

The core vs hardware threads is a murky territory. H designers can do
quiet complex things here - esp between gore/hardware-thread


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