User Guide


Issue: Host Pointer Accessor Used in a Loop

In many algorithms, it is likely that a lot of operations are performed on the device memory and some operations on the host memory. This is particularly true in simulation code where the host memory is updated using a host accessor. This causes many things to happen within the DPC++ run-time where the locks the buffer the accessor points to and updates the copy of this buffer memory on the host device. This pattern of access could cause a lot of memory copies from the device to the host and back in order to keep the data coherent.
Flow Graph Analyzer reports such issues in the following way:
Click the issue to highlight the loop in the graph that consists of a host pointer accessor.
If the buffer pointed by the host pointer accessor is large, the costs incurred due to this access can be a significant portion of each loop.

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