5 ms·

Wall clock time alone isn't such a useful metric to compare CPU vs. FPGA. It would be more meaningful to normalize by machine cost (initial investment and opera

Wall clock time alone isn't such a useful metric to compare CPU vs. FPGA. It would be more meaningful to normalize by machine cost (initial investment and operating costs). (Software development/non-portability is a separate discussion.)

david927 15y ago
Sure, but I think this article tips the hand that something fantastic is possible in this vein. I think a restructuring of foundation-level software, and the kind of movement mentioned here, together would make an amazing combination.
modeless 15y ago
They address software development cost at the end of the paper, and basically conclude that FPGAs are too hard to program to replace CPUs yet, even for highly specialized HPC applications.
- jedbrown 15y ago
  My point is that they should demonstrate what the potential hardware advantage is before evaluating whether the software development costs are worthwhile. There are a few HPC tasks that are very simple and possibly amenable to specialized hardware. D.E. Shaw's Anton is an extreme example of pursuing dedicated hardware. But the metric needs to involve purchasing and power costs for the hardware. FPGAs can come out looking very good in this metric, but comparing raw run times for different systems without cost normalization is meaningless.
  - modeless 15y ago
    I disagree that software development cost shouldn't be considered before hardware cost. The software development costs are so much higher for FPGAs (both money and time) that they probably outweigh the hardware costs for many applications. They are both important and equally worth investigation.
    - jedbrown 15y ago
      If the hardware cost benefit is not large, there isn't any point discussing software development cost. If the benefit is huge, then the software discussion is relevant. In other words, the decision table looks something like HW efficient HW inefficient SW cheap Yes No SW expensive Maybe No

david927 15y ago

Sure, but I think this article tips the hand that something fantastic is possible in this vein. I think a restructuring of foundation-level software, and the kind of movement mentioned here, together would make an amazing combination.

modeless 15y ago

They address software development cost at the end of the paper, and basically conclude that FPGAs are too hard to program to replace CPUs yet, even for highly specialized HPC applications.

jedbrown 15y ago
My point is that they should demonstrate what the potential hardware advantage is before evaluating whether the software development costs are worthwhile. There are a few HPC tasks that are very simple and possibly amenable to specialized hardware. D.E. Shaw's Anton is an extreme example of pursuing dedicated hardware. But the metric needs to involve purchasing and power costs for the hardware. FPGAs can come out looking very good in this metric, but comparing raw run times for different systems without cost normalization is meaningless.
- modeless 15y ago
  I disagree that software development cost shouldn't be considered before hardware cost. The software development costs are so much higher for FPGAs (both money and time) that they probably outweigh the hardware costs for many applications. They are both important and equally worth investigation.
  - jedbrown 15y ago
    If the hardware cost benefit is not large, there isn't any point discussing software development cost. If the benefit is huge, then the software discussion is relevant. In other words, the decision table looks something like HW efficient HW inefficient SW cheap Yes No SW expensive Maybe No