>> Sunday, June 29, 2014
I designed FPGA circuits early in my career and I was surprised by how difficult it can be. The logic elements in an FPGA operate independently, so designers have to keep track of their input/output signals to make sure they're all in step. If Signal A reaches a gate before B and C are valid, the element may produce errors. Timing errors are hard to detect and very difficult to debug. Tools like gdb can't help, so designers use virtual logic analyzers like those provided by Modelsim. OpenCL can reduce the risk and difficulty of FPGA design, but given the small developer base, Intel might not allow developers to access the Xeon's integrated FPGAs. Instead, Intel could assemble a catalog of prebuilt, fully-tested FPGA designs for special tasks. If Intel's C/C++ compiler (icc) notices that an application could be accelerated with one of these designs, it could alert the developer with a friendly dialog box:
Howdy, developer! I see you're sorting database records and performing statistical analysis. If you install Intel's RapidCore on your Xeon, this application will execute 7,364 times faster. Buy RapidCore (Y/N)?After the purchase is completed, the compiler downloads the core from the Internet and automatically installs it on the Xeon's embedded FPGA. This way, the developer doesn't need to understand OpenCL, logic design, or timing analysis. The principle is similar to the downloadable content (DLC) provided by game publishers. After customers buy a game, they can pay extra to make the game easier or more interesting. With Xeon DLC, developers buy the compiler, and then they can improve performance with special-purpose FPGA designs. Similar improvements could be made available to end-users.