[fpc-devel] Vectorization

Adriaan van Os fpc at microbizz.nl
Tue Dec 12 10:24:42 CET 2017

J. Gareth Moreton wrote:
> I created a Wiki page to plan things out: http://wiki.lazarus.freepascal.org/Vectorization

As a side bar, note what Intel writes about Optimization in the Intel Math Kernel Library Developer 

Performance Enhancements

The Intel Math Kernel Library has been optimized by exploiting both processor and system features 
and capabilities. Special care has been given to those routines that most profit from 
cache-management techniques. These especially include matrix-matrix operation routines such as dgemm().

In addition, code optimization techniques have been applied to minimize dependencies of scheduling 
integer and floating-point units on the results within the processor.

The major optimization techniques used throughout the library include:

• Loop unrolling to minimize loop management costs

• Blocking of data to improve data reuse opportunities

• Copying to reduce chances of data eviction from cache

• Data prefetching to help hide memory latency

• Multiple simultaneous operations (for example, dot products in dgemm) to eliminate stalls due to
arithmetic unit pipelines

• Use of hardware features such as the SIMD arithmetic units, where appropriate


Adriaan van Os

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