[Pw_forum] parallel make, was: Re: The NWORDWPP and NWORDWF

[Axel Kohlmeyer]

On Mon, 2009-04-20 at 15:10 +0200, Lorenzo Paulatto wrote:

> Similar errors may also happen if you are using multi process make (make
> -j#), in this case they can be resolved by simpling running make again.


lorenzo,

if you want to use parallel make with Q-E properly, you must not do
"make -j# all" but rather "make MFLAGS=-j# all", which should work
fine, provided the dependencies are correct. i'm doing it all the time
on dual quadcore machines and the compile just "flies". the toplevel
makefile is by no means parallel make safe and it is next to impossible
to do so without changing the behavior completely. i tried quite a long
time ago, and could not make it work. but i got the subdir-makes to
work properly and it has survived since (the complicated looking way of
how the makefile recurses into the subdir with MFLAGS and TLDEPS and
how calling make in the subdir jumps back to the toplevel to check all
dependcies are the result of that).

cheers,
   axel.


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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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If you make something idiot-proof, the universe creates a better idiot.