Re: Build failures with high parallel make(1) jobs with GCC

On Mon, 2014-04-21 at 22:54 -0400, Glen Barber wrote:
> I have been pounding my head against the desk for longer than I care to
> admit with this failure.
> 
> I see this with powerpc, powerpc64, and now ia64.  I initially thought
> it was specific to powerpc{,64}, but now realize ia64 is also affected.
> 
> This build was running with -j48 on a 48-core machine, when the
> following caused build failure:
> 
> =======================================================================
> 
> /usr/obj/ia64.ia64/usr/src/tmp/usr/bin/ld: cannot find -lm
> --- libstdc++.so.6 ---
> *** [libstdc++.so.6] Error code 1
> 
> make[4]: stopped in /usr/src/gnu/lib/libstdc++
> A failure has been detected in another branch of the parallel make
> 
> =======================================================================
> 
> It is unclear to me when exactly this started happening, but it seems at
> least two weeks is a reasonable estimate.
> 
> I realize this is not an entirely large chunk of useful information
> regarding the build failure, but I have determined it is entirely
> reproducible.  I have determined that the failure case seems to
> disappear with make(1) jobs <= 10, at least for powerpc.
> 
> The last successful build for powerpc on head/ was April 8.  But I am
> having trouble tracking down what commits may (or may not) have
> contributed to recent high-parallel build failures.
> 
> Glen
> 

A couple weeks corresponds somewhat with the parallel subdir build
changes (it's about 3 weeks now).  Try this patch I cooked up today for
$work, and in src/lib/Makefile add .WAIT (as if it were a directory
name) between ${SUBDIR_ORDERED} and the rest of the directories.

-- Ian