Developer Guide


Restrictions of Pipes

The following table summarizes restrictions of pipes:
Restrictions of Pipes
Multiple Pipe Call Sites
A kernel can read from the same pipe multiple times. However, multiple kernels cannot read from the same pipe. Similarly, a kernel can write to the same pipe multiple times, but multiple kernels cannot write to the same pipe.
Feedback and Feed-Forward Pipes
Within a single kernel, you should either read from a pipe or write to a pipe. Writing and reading to the same pipe within a single kernel may lead to poor performance.
Emulation Support
The FPGA emulator supports emulation of kernels that contain pipes. For better conformity between emulation and hardware, provide a non-zero pipe capacity while specializing a pipe type. For more information about the Emulator, refer to the Intel® oneAPI Programming Guide.
If the same kernel is invoked more than once, the FPGA emulator may attempt to execute kernels concurrently, resulting in a data race if both invocations attempt to read or write from the same pipe. This issue affects only emulation. In the hardware flow, multiple invocations of the same kernel are executed serially. To work around this issue, add a call to the
function between executions of the same kernel.

Product and Performance Information


Intel's compilers may or may not optimize to the same degree for non-Intel microprocessors for optimizations that are not unique to Intel microprocessors. These optimizations include SSE2, SSE3, and SSSE3 instruction sets and other optimizations. Intel does not guarantee the availability, functionality, or effectiveness of any optimization on microprocessors not manufactured by Intel. Microprocessor-dependent optimizations in this product are intended for use with Intel microprocessors. Certain optimizations not specific to Intel microarchitecture are reserved for Intel microprocessors. Please refer to the applicable product User and Reference Guides for more information regarding the specific instruction sets covered by this notice.

Notice revision #20110804