Ævar Arnfjörð Bjarmason [off-list ref] 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.
quoted hunk
+### 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