+/* Do not generate a prefetch if the unroll factor is significantly less
+ than what is required by the prefetch. This is to avoid redundant
+ prefetches. For example, if prefetch_mod is 16 and unroll_factor is
+ 1, this means prefetching requires unrolling the loop 16 times, but
+ the loop is not going to be unrolled. In this case (ratio = 16),
+ prefetching is not likely to be beneficial. */
+
+#ifndef PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO
+#define PREFETCH_MOD_TO_UNROLL_FACTOR_RATIO 8
+#endif
+