[Wien] Parallel make (make -j 4)

[Fecher, Gerhard]

Hallo Laurence,
did you check the make description on
    https://www.gnu.org/software/make/manual/html_node/Parallel-Disable.html
there are two rules that influence the behaviour of parallel make that are
.NOTPARALLEL and .WAIT

I am not completely sure about your intentions, 
If the modul files do not depend on each other (hopefully) then you can compile them in parallel and do the remaining job afterwards.
Below is a  snippet of a makefile that I use (be sure that my MODS and OBJS contain many more files: > 20)
using make -j 12 eos0 (or scf0) will fail, whereas make -j 12 eos (or scf) or make -j N all (N is the number of parallel processes) work fine
the .WAIT is not ncessary, the rules mods0 scf0 eos0 are serially processed in all:
that is, the module files are compiled before the remaining part is worked on.

If some modules depend on each other you may either split the module files into groups or you may use a .NOTPARALLEL: rule applied only on the module files (I never tested that).

FC=
LINK = ...
LIBRARIES=...
.f.o:
	$(FC)   $<  -o $@

########################

MODULES = module_1.o     \
          ... etc

OBJS    = object_1.o     \
          ... etc

# many objects
SCF  = $(MODS) $(OBJS)

# a single object
EOS  = $(MODS) eos.o

########################

all: mods0 scf0 eos0

# or all: mods0 .WAIT scf0 eos0

# the following may be used to allow making of scf and eos independently with parallel make
# all: scf eos
# scf: mods0 .WAIT scf0
# eos: mods0 .WAIT eos0

########################

.WAIT:

# compile the modules 
mods0: $(MODS)


# compile the remaining parts and make the binaries
scf0:	$(BIN)/scf
	@echo " "

$(BIN)/scf: $(SCF) 
	 $(LINK) $(LIBRARIES) $(SCF) -o $(BIN)/scf

eos0:	$(BIN)/eos
	@echo " "

$(BIN)/eos: $(EOS) 
	 $(LINK) $(LIBRARIES) $(EOS) -o $(BIN)/eos

... etc



Ciao
Gerhard

DEEP THOUGHT in D. Adams; Hitchhikers Guide to the Galaxy:
"I think the problem, to be quite honest with you,
is that you have never actually known what the question is."

====================================
Dr. Gerhard H. Fecher
Institut of Physics
Johannes Gutenberg - University
55099 Mainz
________________________________________
Von: Wien [wien-bounces at zeus.theochem.tuwien.ac.at] im Auftrag von Laurence Marks [laurence.marks at gmail.com]
Gesendet: Montag, 10. März 2025 15:02
An: A Mailing list for WIEN2k users
Betreff: [Wien] Parallel make (make -j 4)

It would be useful to exploit parallel make. However, currently in each SRC_* there are several files with modules which have to be compiled first. Searching the Internet I have yet to see a good source/docs for how to have a few files compiled serially, then the rest done in parallel. I am looking for suggestions of sources for these (direct to me is best), and/or edits for one of the simpler SRC. I can test then, perhaps, we can add for all of W2k.

___
Emeritus Professor Laurence Marks (Laurie)
Department of Materials Science and Engineering, Northwestern University
www.numis.northwestern.edu<http://www.numis.northwestern.edu>
"Research is to see what everybody else has seen, and to think what nobody else has thought" Albert Szent-Györgyi