Intel ARCHITECTURE IA-32 User Manual

Page 551

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Mathematics of Prefetch Scheduling Distance

E

E-5

T

l

varies dynamically and is also system hardware-dependent. The static

variants include the core-to-front-side-bus ratio, memory manufacturer
and memory controller (chipset). The dynamic variants include the
memory page open/miss occasions, memory accesses sequence,
different memory types, and so on.

To determine the proper prefetch scheduling distance, follow these steps
and formulae:

Optimize T

c

as much as possible

Use the following set of formulae to calculate the proper prefetch
scheduling distance:

Schedule the prefetch instructions according to the computed
prefetch scheduling distance.

For optimized memory performance, apply techniques described in
“Memory Optimization Using Prefetch” in Chapter 6.

The following sections explain and illustrate the architectural
considerations involved in the prefetch scheduling distance formulae
above.

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