AMD 250 manual Guideline, Key Optimizations by Rank

Software Optimization Guide for AMD64 Processors 25112 Rev. 3.06 September 2005

1.5Key Optimizations

While all of the optimizations in this guide help improve software performance, some of them have more impact than others. Optimizations that offer the most improvement are called key optimizations.

Guideline

Concentrate your efforts on implementing key optimizations before moving on to other optimizations, and incorporate higher-ranking key optimizations first.

Key Optimizations by Rank

Table 1 lists the key optimizations by rank.

Table 2.	Optimizations by Rank
Rank	Optimization	Page
1	Memory-Size Mismatches	92
2	Natural Alignment of Data Objects	95
3	Memory Copy	120
4	Density of Branches	126
5	Prefetch Instructions	104
6	Two-ByteNear-Return RET Instruction	128
7	DirectPath Instructions	72
8	Load-Execute Integer Instructions	73
9	Load-ExecuteFloating-Point Instructions with Floating-Point Operands	74
10	Load-ExecuteFloating-Point Instructions with Integer Operands	74
11	Write-combining	113
12	Branches That Depend on Random Data	130
13	Half-Register Operations	356
14	Placing Code and Data in the Same 64-Byte Cache Line	116

6 Introduction Chapter 1