Quote:> Could someone take a few sentences to explain how the
> dual-Pentium motherboards divide the work between the two
> processors to speed the throughput? I understand that
> Windows NT can make use of two processors, but how does it
> differentiate between them? Do they each have a separate
> data bus so that they can operate in parallel? Any info
> on how dual-processor boards operate would be appreciated.
> Thanks.
> Phil
How work is divided among processors in a multiprocessor system is entirely
depenedent on the operating system. A symmetric multiprocessing OS (SMP)
will divide the jobs, the I/O and the OS itself over all available cpus. This
is being worked on for Linux.
There is generally only one datapath to memory (I haven't seen a system
smaller than a mainframe with a dual-ported mainstore, this is horrifically
expensive) but since each CPU has its own caches, they operate in parallel
most of the time by running out of their cache.
The fact that there is only one datapath to memory, and the periodic need to
sync up the processors are some of the reasons that two processors are NOT
twice as fast as one.
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| | To see a world in a grain of sand, |
| Gary Ward | And a heaven in a wild flower, |
| | And eternity in an hour. |
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