Visible to Intel only — GUID: GUID-0A3F3CCB-3275-4212-9A70-0DD04043231A
Visible to Intel only — GUID: GUID-0A3F3CCB-3275-4212-9A70-0DD04043231A
qopt-prefetch-distance, Qopt-prefetch-distance (ifx only)
Specifies the prefetch distance to be used for compiler-generated prefetches inside loops. This description is only for ifx.
Syntax
Linux: |
-qopt-prefetch-distance=n |
macOS: |
None |
Windows: |
/Qopt-prefetch-distance:n |
Arguments
n |
Is the prefetch distance in terms of the number of (possibly-vectorized) iterations. Possible values are non-negative numbers >=0. n = 0 turns off all compiler issued prefetches from memory to L1. |
Default
OFF |
The compiler uses default heuristics to determine the prefetch distance. |
Description
This option specifies the prefetch distance to be used for compiler-generated prefetches inside loops. The unit n is the number of iterations. If the loop is vectorized by the compiler, the unit is the number of vectorized iterations.
The value of n will be used as the distance for prefetches from memory to L1 (for example, the vprefetch0 instruction).
Linux
This option is ignored if option -qopt-prefetch=0 or option -qno-opt-prefetch is specified.
Windows
This option is ignored if option /Qopt-prefetch=0 or option /Qopt-prefetch- is specified.
IDE Equivalent
Alternate Options
None
Examples
Consider the following Linux examples:
-qopt-prefetch-distance=24
The above causes the compiler to use a distance of 24 iterations for memory to L1 prefetches.
-qopt-prefetch-distance=0
The above turns off all memory to L1 prefetches inserted by the compiler inside loops.
-qopt-prefetch-distance=16
The above causes the compiler to use a distance of 16 iterations for memory to L1 prefetches.