> How does idle time accrue *to a process*? Idle time is when the CPU is not
> executing any process.
in virtually every multitasking OS, there is a special "IDLE" process. This
is usually something as simple as...
idleloop:
HLT
JMP idleloop
and this process is always 'ready' to run, and always at the LOWEST system
priority [many OS's have a special 'Idle' priority used only for this
process]. That way the task dispatcher *always* has somewhere to go if no
other process is ready. The "HLT" instruction will be awoken at the very
next interrupt, and since anything that can cause a process to wake up
neccessarily involves a interrupt, this means no time is wasted. HLT also
causes most CPUs to enter a reduced power state, running many degrees cooler
(when I exit prime95, my P3-933 goes from ~118F to ~80F in a very short
time).
-jrp
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