[petsc-dev] [Ideas-team] Seeking OLCF users complaining about poor build times

[Barry Smith]

> On Feb 27, 2015, at 12:00 PM, Jed Brown <jed at jedbrown.org> wrote:
> 
> Barry Smith <bsmith at mcs.anl.gov> writes:
>>   Actually the parallel compiles of the 1000+ files on the "regular"
>>   filesystems at ANL and LBL is taking less than 2 minutes so I can't
>>   blame the filesystem bandwidth.
> 
> I think bandwidth is adequate, but latency (especially for metadata) is
> rather high.  Normal make uses parallelism to mitigate, but configure is
> sequential, so gets hit harder.

    Yup, that was my conclusion. So the solution is 1) apply pressure to improve latency on these systems a bit and 2) incorporate more parallelism in ./configure without making it even more complicated.  Or switch to cmake where you don't test anything but just read the machines capabilities from an outdated database :-).

  Barry