Follow-up Comment #3, bug #57575 (project make):
All that means is that it's harder to get exactly the right number of jobs to
run in parallel without -l.
The -l option doesn't change anything except add an extra test that make
checks to see if it can run a job. So instead of "I have a job to run, have I
exceeded my -j level?", make uses "I have a job to run, have I exceeded my -j
level OR is the load higher than the -l setting?" That's the only difference
with and without -l. There's no difference in the order in which jobs are
selected to be run.
Just to note, that a load of 0.5 when you have 8 CPUs is pretty small. A
setting of "-j8 -l0.5" basically tells make "run 8 jobs in parallel BUT if the
load is higher than one half of one CPU's worth, don't start more".
Load averages on multi-core systems are something of a dark art but _more or
less_ you get 1 for every core. So if you had 8 cores and they were 100% busy
with no other processes waiting to run you'd expect your load average to
approach 8.
You may be thinking that the load is averaged across CPUs so that a load of
1.0 means "all CPUs busy" and 0.5 means you want about half your system to be
busy but that's not how it works.
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