Re: make: should -j affect cwd?

[David Holland <dholland-tech%netbsd.org@localhost>]

On Wed, Jan 18, 2012 at 01:58:41PM -0500, Mouse wrote:
 > > # pwd
 > > /usr/src/lib/libc
 > > # time make -n > /dev/null
 > > 1.408u 0.470s 0:01.87 100.0%    0+0k 0+0io 0pf+0w
 > > # 
 > 
 > > That's a pretty fast amd64.  The fact that it takes a measurable
 > > amount of time means it's really damn slow on a vintage box.
 > 
 > Unless stat results for everything relevant were already in core, I
 > suspect that's dominated by waiting for disk, in which case it may not
 > be all that much slower on a vintage box, assuming of course the
 > vintage box has a decent disk interface; even my slow machines often
 > have spare CPU cycles when doing that kind of workload.

Well, as Christos pointed out it does a lot more stat calls than
necessary. But that was with a warm cache.

IME from years ago it can take quite a while to do a null make in libc
on slower machines.

Also, what we'd really like is to to be able to do things like 'make
show-downlevel' from /usr/pkgsrc without it taking a minor or major
eternity.

-- 
David A. Holland
dholland%netbsd.org@localhost