gcc - How to determine a good value for --load-average using gnu Make? -

exists in this flag:

-l [load], --load- The average [= load] specifies that any other jobs (commands) should not be started, if the other tasks are running and the load average is less than the load (a floating-point number) with no logic , Removes the previous load limit.

Is there a good strategy for the value that you use for the load limit? It seems that there is a lot of different between my machines.

I -l option.

In theory, -l looks better than -j . -j says, they start many jobs, -l says, make sure that many jobs are running. Often, this is almost the same thing, but when you have I / O bound work, there is another strange thing, then -l should be better.

He said, the concept of load is a bit suspicious, it is necessary that the sample of what is going on on the system. So if you run make -j -l N (some N ) and you have a well-written mess file, then immediately start a large number of tasks Before and after the system load, the sample can also be moved, before the file is out of the details or memory. Also, the accounting of the load average varies in the operating system, and some obscure people do not have it at all.

In practice, you will have -j and fewer headaches. To get more performance from creation, tune your makefile, play with compiler options, and use cakes or similar.

(The root cause for the -l option is doubted when multiple processors were scarce and I / O was actually slow.)