RE: suddenly, "recursive make considered harmful" makes piles of sense

[twk]

[Boris Kolpackov:]
> There is also a third "philosophy": gmake within any directory will
> build that directory and all its dependencies and any subdirectories
> and all their dependencies.

[Paul D. Smith:]
> One disadvantage to this method is that in order for it to work every
> time you run make it has to read ALL the makefiles.

[Boris Kolpackov:]
> Have you tried to profile this? I believe opening and reading 800 file
> on a modern UNIX system is not a big deal per se.

FWIW, with 80 makefiles (comprising ~3500 lines combined)
plus 920 .d files (also -included, comprising 127,000 lines combined)
I find the response of this kind of make system instantaneous on our Linux
machines but erratic on our XP machines.  On XP if I have done a make
"recently", the response is instantaneous but the first make in the morning
takes up to a minute to read all the makefiles and stat all the dependency
files.  Anything which eats a lot of virtual memory will cause the next
make to be slow again.

All machines are ~2.6 Ghz Xeons, using make 3.80.


--
Tom Kronmiller