diff options
| -rw-r--r-- | docs/Vectorizers.rst | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/docs/Vectorizers.rst b/docs/Vectorizers.rst index b4c5458..d679ca4 100644 --- a/docs/Vectorizers.rst +++ b/docs/Vectorizers.rst @@ -208,15 +208,14 @@ Partial unrolling during vectorization ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Modern processors feature multiple execution units, and only programs that contain a -high degree of parallelism can fully utilize the entire width of the machine. - +high degree of parallelism can fully utilize the entire width of the machine. The Loop Vectorizer increases the instruction level parallelism (ILP) by performing partial-unrolling of loops. In the example below the entire array is accumulated into the variable 'sum'. -This is inefficient because only a single 'adder' can be used by the processor. +This is inefficient because only a single execution port can be used by the processor. By unrolling the code the Loop Vectorizer allows two or more execution ports -to be used. +to be used simultaneously. .. code-block:: c++ |