Application performance has been and remains one of top five concerns since the inception of cloud computing. A primary determinant of application performance is multitenancy or sharing of hardware resources in clouds. While some hardware resources can be partitioned well among VMs (such as CPUs), many others cannot (such as memory bandwidth). In this paper, we focus on understanding the variability in application performance on a cloud and explore ways for an end customer to deal with it.

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... on rigorous experiments using CloudSuite, a popular Web2.0 benchmark, running on EC2, we found that interference-induced performance degradation is a reality. On a private cloud testbed, we also observed that interference impacts the choice of best configuration values for applications and middleware. We posit that intelligent reconfiguration of application parameters presents a way for an end customer to reduce the impact of interference. However, tuning the application to deal with interference is challenging because of two fundamental reasons -the configuration depends on the nature and degree of interference and there are inter-parameter dependencies. We design and implement the IC 2 system to address the challenges of detection and mitigation of performance interference in clouds. Compared to an interferenceagnostic configuration, the proposed solution provides upto 29% and 40% improvement in average response time on EC2 and a private cloud testbed respectively.