Re: GNU make 4.2.90 release candidate available

[Paul Smith]

On Mon, 2019-08-26 at 10:26 -0700, David Boyce wrote:
> > the -l/--load-average option will use the contents of that file to
> determine how many jobs are running at any given instant, and compare
> that value to the load value requested.
> 
> Compare and do what? This doesn't make sense to me.

I guess this is confusing.  It means, if there are N processes
currently executing on a core (not waiting) then only start a new job
if -l is >= N (equal to because one active process is make itself so we
don't count it).

> > This allows usage such as "-j -lN" for N-processor systems without
> fear of overload.
> 
> There's never a fear of overload when explicitly specifying -lN for
> an N-processor system, is there?

If you use -lN -j, make can kick off enough jobs to kill your system
before the load average can change enough to throttle it.  The most
specific value we can get from getloadavg() is an average over the last
minute.  Admittedly there are other heuristics we try to use to make it
more accurate than that.

> > It will select POSIX_SPAWN_USEVFORK where that is available....
> 
> Does this mean that the autotools config system will select
> POSIX_SPAWN_USEVFORK? That's not a behavior of GNU make per se.

Yes, autoconf will detect and use it.  I'm not sure I understand the
comment.