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

[Todd Gamblin]

CMake test stuff too, so it has the same problem.  At the very least it
tests the compiler id and ends up creating a bunch of directories and
files in the CMakeFiles directory.

So you're still in the same boat with CMake... But you don't have to
maintain your own elaborate build system on the side.

On 2/27/15, 10:06 AM, "Barry Smith" <bsmith at mcs.anl.gov> wrote:

>
>> 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capabilities from an outdated database :-).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
>
>