On Wed, 18 Oct 2017, FX wrote: > Parallel builds of libstdc++ on APFS filesystem (with 1 ns granularity) on > macOS 10.13 often fail (failure rate for ?make -j2? to ?make -j8? is about > 60% from my own builds and results reported by others): > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81797 > This is reproducible with several versions of GNU make. > > Changing libstdc++?s makefile to mark install-headers with .NOTPARALLEL fixes > the issue. We've carried that patch in Homebrew (https://brew.sh) for a few > months now, and have had no report of build issues since then. > > Bootstrapped and regtested on x86_64-apple-darwin17 (as well as other > platforms). OK to commit?
Maybe moot now, but .NOTPARALLEL doesn't work the way you imply in the patch. From TFM of GNU Make 3.81 and 4: "Any prerequisites on this target are ignored." To wit, it seems you'd get the effect, but for *every target* in this Makefile. (If I were you and the patch is still proposed, I'd remove the unused target and add a comment on the intent.) Assuming the documentation and my reading is correct. brgds, H-P
