Intel® oneAPI DPC++ FPGA Optimization Guide

Developer Guide

Contents

Specify Schedule F
MAX
 Target for Kernels

The schedule f
max
 target determines the pipelining effort the scheduler attempts during the scheduling process.
You can use one or both of the following options to specify the kernel specific f
max
 target:
  • By using the
    [[intel::scheduler_target_fmax_mhz(
    N
    )]]
     source-level attribute.
  • By directing the
    Intel® oneAPI
    DPC++/C++
     Compiler
     to globally compile all kernels
    -Xsclock=<clock target in Hz/KHz/MHz/GHz or s/ms/us/ns/ps>
     option in the
    dpcpp
     command.
If you use both the command-line option and source-level attribute, the kernel attribute takes the priority. Consider the following example: 
cgh.single_task<class mykernel1>([=] {
  ...
});

cgh.single_task<class mykernel2>([=
]() [[intel::scheduler_target_fmax_mhz(200)]] {
  ...
});
In you direct the compiler to compile the above code with
–Xsclock=300MHz
 in the
dpcpp
 command, the compiler schedules kernel
mykernel1
 at 300 MHz and kernel
mykernel2
 at 200 MHz.
The schedule target f
max
 determines the pipelining effort during compilation. Refer to the Quartus compilation summary in the
report.html
 file to get the actual f
max
 value.

Product and Performance Information

1

Performance varies by use, configuration and other factors. Learn more at www.Intel.com/PerformanceIndex.