[Default] On 4 May 2017 11:18:43 -0700, in bit.listserv.ibm-main [email protected] (Mark Post) wrote:
>>>> On 5/4/2017 at 09:56 AM, Phil Smith <[email protected]> wrote: > >> http://www.bbc.com/news/technology-39803425 >> >> So my question on this is, "If this old code ran anywhere near to acceptably >> when it was written, how can it possibly not be fast enough on modern >> hardware?!" > >My guess would be that over time the types of simulations they run are more >involved and take much longer. Given that the current hardware is as follows: >System Architecture > Manufacturer: SGI > 161 racks (11,472 nodes) > 7.25 Pflop/s peak cluster > 5.95 Pflop/s LINPACK rating (#13 on November 2016 TOP500 list) > 175 Tflop/s HPCG rating (#9 on November 2016 HPCG list) > Total CPU cores: 246,048 > Total memory: 938 TB > 2 racks (64 nodes total) enhanced with NVIDIA graphics processing units > (GPUs) > 184,320 CUDA cores > 0.275 Pflop/s total > 1 rack (32 nodes total) enhanced with Intel Xeon Phi co-processors (MICs) > 3,840 MIC cores > 0.064 Pflop/s total > >and they're talking about current run times of "hundreds" of hours or longer, >I don't think they'll be running any of this on a mainframe. > Since this is old Fortran, I suspect that the given simulation can only use one core. It also may be limited in the memory it can use or does use. Having a good optimizing compiler would help and one may or may not be available for the box used. There may be code which was optimal for the environment in existence when written but counter-productive in the current environment. I know that optimization that I did for COBOL VS was in some ways counter-productive in VS COBOL II 1.4 and later. Clark Morris > >Mark Post > >---------------------------------------------------------------------- >For IBM-MAIN subscribe / signoff / archive access instructions, >send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
