Add jobs.mk to allow for target-jobs

[sjg]

Summary

jobs.mk automates -j$JOB_MAX and capturing build log based on target.

[imp]

Makefile

122

This seems out of place relative to the above comment. Maybe move it to before this comment and add a comment saying what the heck is going on.

share/mk/jobs.mk

34

is that 'normal' done inside of make(1) or a user's build env?

37

how does this even work? There's no date command...

[sjg]

Makefile

122

I took the preceding comment as general info for the whole makefile?
I can certainly add a comment, but moving up above that big comment didn't seem appropriate . I could move it later, but you sort of want to do this include early to avoid wasting effort.

share/mk/jobs.mk

34

You could do it either way - we do it in env, but you could just as easily put something in local.sys.mk or any other makefile via sys.mk

FYI in the past when we had shared build machines the logic to set JOB_MAX took into account how many builds were already running on a machine.

37

:gmtime is a bmake modifier, the above is equivalent to doing strftime %s

[sjg]

Add comment to src/Makefile

[imp]

OK. I'm a little nervous about -j 8 being the default. Isn't there some way that the default could be derived from hw.ncpu?

And cool about the gmtime... I learned a thing.

[sjg]

In D39683#903570, @imp wrote:

OK. I'm a little nervous about -j 8 being the default. Isn't there some way that the default could be derived from hw.ncpu?

And cool about the gmtime... I learned a thing.

I can add something to local.sys.env.mk or similar to do that

[sjg]

Provide JOB_MAX default derrived from ncpu

[sjg]

Use JOB_MAX_FACTOR 1.33 and add UPDATING entry