Benefits of I/O Acceleration Technology (I/OAT) in Clusters ∗

Packet processing in the TCP/IP stack at multi-Gigabit data rates occupies a significant portion of the system overhead. Though there are several techniques to reduce the packet processing overhead on the sender-side, the receiver-side continues to remain as a bottleneck. I/O Acceleration Technology (I/OAT), developed by Intel, is a set of features particularly designed to reduce the receiver-side packet processing overhead. This paper studies the benefits of the I/OAT technology by extensive evaluations through micro-benchmarks as well as evaluations on two different application domains: (1) A multitier data-center environment and (2) A Parallel Virtual File System (PVFS). Our micro-benchmark evaluations show that I/OAT results in 38 % lower overall CPU utilization in comparison with traditional communication. Due to this reduced CPU utilization, I/OAT delivers better performance and increased network bandwidth. Our experimental results with data-centers and file systems reveal that I/OAT can improve the total number of transactions processed by 14 % and throughput by 12%, respectively. In addition, I/OAT can sustain a large number of concurrent threads (up to a factor of four as compared to non-I/OAT) in data-center environments, thus increasing the scalability of the servers.