Decorated Operations for QorIQ P3/P4/P5 Processors - Freescale ...

Introduction
Statistics acceleration with the use of decorated operations solves the initial problem without the need for
locks. This drastically increases performance and lowers the software complexity, because all protection
for issues related to locks can be removed.
1 Introduction
Currently, the industry is rapidly migrating to multicore solutions, largely due to the fact that easy
single-core performance improvements using stronger or faster cores is coming to an end. Further
improvements to code execution (instructions per cycle) introduce drastically more complex logic.
Increasing the frequency is difficult, because power consumption increases to the power of two relative
the frequency1 . Furthermore, higher frequency gives little additional performance due to the core/memory
speed difference [1].
Multicore solutions give a theoretically higher performance with low aggregate power consumption, but
it is crucial that the hardware and software is designed to allow for efficient scaling. The most important
hardware aspects are buses and memory interfaces; in this area, the concept of switch fabrics is replacing
traditional buses. For example, Freescale’s P4080 communication processor, equipped with eight e500mc
Power Architecture® cores, solves this problem by utilizing the CoreNet coherency fabric with nearly 1
Tbps of internal memory bandwidth and dual DDR3 interfaces. The other aspect, software design, is
difficult to solve on a general basis to allow efficient scaling. Amdahl’s law [2] describes the application
speed-up relative to the number of cores and how well parallelized the software is. As shown in Figure 1,
software that is largely sequential can never make efficient use of highly parallel architectures. Therefore,
it is critical to provide means to remove sequential sections.
Figure 1 shows Amdahl’s law of scaling over multiple cores for different degrees of parallelized code. S
marks the portion of sequential code.
Figure 1. Amdahl’s Law
1. Relation is P = CV 2 F, but higher frequency requires higher voltage and leakier processes.
Decorated Operations for QorIQ P3/P4/P5 Processors, Rev. A
2 Freescale Confidential Proprietary Freescale Semiconductor
Preliminary—Subject to Change Without Notice