IBM J. Res. Dev

Applying Amdahl's other law to the data center

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As computing system workloads become more distributed in nature, there is an increasing dependence on the networking interconnects between such systems. As stated by Amdahl's Other Law, this dependence not only exists on the I/O (input/output) subsystem, but also on the memory subsystems. In particular, as processor utilization increases, there is a direct, corresponding increase in memory and I/O utilization. At a broader level, the distribution of workloads is driving the need for computing based on locality (or pods) to achieve the appropriate balance of compute, network, and storage resources. This paper studies the applicability of Amdahl's Other Law to the data center to better understand the relationship between processor systems and the networks interconnecting them. This study is also relevant as multicore systems will become more prevalent to sustain growth of processing performance. © 2009 IBM.