Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx> writes: > Override built-in rules of GNU make that use a wildcard target. This > can speeds things up significantly as we don't need to stat() so many > files. GNU make does that by default to see if it can retrieve their > contents from RCS or SCCS. See [1] for an old mailing list discussion > about how to disable these. ;-) > The speed-up may wary. I've seen 1-10% depending on the speed of the vary, you mean? > local disk, caches, -jN etc. Running: > > strace -f -c -S calls make -j1 NO_TCLTK=Y > > Shows that we reduce the number of syscalls we make, mostly in "stat" > calls. Naturally understandable. I do remember getting surprised after seeing output from "make -d" and how many paths were considered for possible places that a source file can come from. > +### Remove GNU make implicit rules > + > +## This speeds things up since we don't need to look for and stat() a > +## "foo.c,v" every time a rule referring to "foo.c" is in play. See > +## "make -p -f/dev/null | grep ^%::'". > +%:: %,v > +%:: RCS/%,v > +%:: RCS/% > +%:: s.% > +%:: SCCS/s.% > + > ### Flags affecting all rules > > # A GNU make extension since gmake 3.72 (released in late 1994) to
