> I guess this is confusing ... There may be confusion in the text between "the number of jobs running" and "the number of jobs running *on a core*".
> 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. Understood. > I'm not sure I understand the comment. This section says "GNU make will now use pthread_spawn() on systems where it is available ... It will select ...", thus "it" refers to GNU make. But GNU make will not do this at runtime (IIUC), the config system will do so at compile time. I think this could be clarified. In all of these the main point is for the release text to be as clear as possible; it's not about explaining it to me. As long as you're satisfied it's clear I'm happy to let it go. On Mon, Aug 26, 2019 at 11:08 AM Paul Smith <psm...@gnu.org> wrote: > 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. > >
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