[ Thanks to Ken
Treis for this link. ]
“Linux SMP support has been smoothed out in the stable
kernel since the release of 2.2 — and dual Celeron 533s (plus a
motherboard) can be obtained for less than $330 USD — so what does
that mean for your next system purchase? The Signal Ground
team dives head-first into the world of SMP, looking for real-world
price-to-performance data.”
“In a Linux SMP system, the Linux kernel automagically manages
the use of all processors. Unfortunately, the primary function of a
CPU — processing a stream of instructions — doesn’t lend itself
very well to sharing. The sharing of one instruction stream is like
two people (A and B) trying to share a computer terminal while
interacting with you (C) at the counter in a bank. Perhaps upper
management at this bank has decided that the two brains behind the
counter should be able to serve individual customers twice as
quickly. In reality, though, we know that even if A and B knew each
other extremely well, the overhead of their communication would
cause your transaction to take even longer to process.”
“Instead of working like the crazy managers that I just
described, SMP systems delegate entire tasks to individual
processors. This is more like the real-world situation at a bank.
When you arrive at the bank, you are greeted by the first available
teller. If teller A is busy, you can meet with teller B to have
your request processed. If both tellers are busy, you wait. If
neither is busy, the prettier one processes your request while the
other waits.”