应用Amdahl定律对多核处理器性能的分析  

Analysis of performance for multi-core processors by Amdahl's law

作　　者：刘俊[1] 刘志祥[1] 

机构地区：[1]沈阳化工学院计算机科学学院,沈阳110142

出　　处：《信息技术》2010年第6期232-234,共3页Information Technology

摘　　要：随着技术的发展,多核心处理器已成为现今处理器发展的潮流。提高处理器性能的方法有许多,其中主要有提高频率与增加核心数量等。提高频率在现有条件下已经比较困难且不经济,增加核心数量之路又能走多远。加速比是衡量系统性能提升的一个重要指标,Amdahl定律便是其中之一。在Amdahl定律的范围内(且不考虑包括通讯开销等在内的并行开销),通过对单一核心提高频率和增加核心数量两个方面的讨论可以得出:在可并行执行部分的执行时间占总执行时间的比例f=0.5时,提高单一核心频率与增加核心所得加速比相同;当f<0.5时,提高单一核心频率可比增加核心数量获得更大加速比;当f>0.5时,增加核心数量获得的加速比更大些。因此,在核心数量增加到一定程度时,通过提高单一核心的频率可获得更高加速比,也可能是更经济有效的方案。With the development of technology,multi-core processors have become the processor＇s development trend of today.To improve processor performance,there are many ways among which to improve the frequency and to increase the number of cores are mainly ones.To improve the frequency under the present conditions is difficult and uneconomic,and how far can it go to increase the number of cores.Speed-up ratio is an important indicator of system performance＇s improvement,and Amdahl＇s law is one of them.In the context of Amdahl＇s law（not to consider parallel overhead charges including the communication overhead charges etc.）,through discussing the two ways,to improve the single core＇s frequency or to increase the number of the core,it can be drawn： when the proportion（f） of parallel execution time＇s to total execution time is 0.5（f=0.5）,increasing the single-core＇s frequency or increasing the number of cores can get the same speed-up ratio;when f0.5,speed-up ratio of increasing the single-core＇s frequency is greater than speed-up ratio of increasing the number of cores;when f0.5,increasing the number of cores can obtain the greater speed-up ratio.Thus,the number of the cores increased to a certain extent,by increasing the frequency of single-core can obtain of a higher speed-up ratio,it may be a more cost-effective solution.

关 键 词：加速比 多核 AMDAHL定律 体系结构 

分 类 号：TP303[自动化与计算机技术—计算机系统结构]