Developer Guide

Contents

Global Memory

If the kernel code accesses a host-allocated buffer, the compiler creates a hardware interface through which the datapath accesses the buffer in global memory. A host-allocated buffer resides in device global memory off-chip. The code snippet in the Kernel Memory section shows a device global memory and its accesses within the kernel.
Unlike kernel memory, the compiler does not define the structure of a buffer in global memory. The compiler instantiates a specialized LSU for each access site based on the memory access pattern to maximize the efficiency of data accesses.
All accesses to global memory must go through the hardware interface. The compiler connects every LSU to an existing hardware interface through which it transacts with device global memory. Since the compiler cannot alter that interface or create more such interfaces, it must share the interface between multiple datapath reads or writes, which can limit the throughput of the design. The strategies used by the compiler to maximize efficient use of available memory interface bandwidth include (but are not limited to) the following:
  • Eliminating unnecessary accesses.
  • Statically coalescing contiguous accesses.
  • Generating specialized LSUs that can perform the following:
    • Dynamically coalesced accesses that fall within the same memory word (as defined by the interface).
    • Prefetch and cache memory contents.

Product and Performance Information

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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