Way back when I had a Cyrix chip and one nice thing about it was that when the OS did a HLT in
the idle loop (which linux did at the time) the power usage dropped significantly. Which was
good since these chips had a nasty habit of overheating when you tried to do anything complex.
Is this something they did and no-one ever followed up on? Because it seemed to me like a
rather obvious idea that everyone would do, but it seems I'm wrong... Seems rather a lot
easier than switching sleep states several times per second.
Posted May 11, 2008 14:36 UTC (Sun) by mjg59 (subscriber, #23239)
[Link]
C states are effectively a more advanced implementation of the hlt instruction. C1 is
equivalent to hlt, with deeper states disabling more of the CPU and introducing more latency.