1. 1 WAN Network Researches Wenji Wu, Phil Demar wenji@fnal.govwenji@fnal.gov, demar@fnal.govdemar@fnal.gov Fermilab Nov 30, 2007

2. 2 Mission …to provide and support wide-area networking, and network infrastructure for the scientific computing facilities with extreme WAN bandwidth requirements WAN Network Researches

3. 3 Performance analysis of Linux networking – packet Receiving Potential performance bottleneck in Linux TCP Interactivity vs. fairness in networked Linux systems Focus: Linux kernel issues in network end hosts – interactions among network processing, interrupt handling, process scheduling and memory management. Applied results: better network tuning, guidance on memory allocation, debugging of complex systems, and network performance enhancement methodology Previous Research Projects

4. 4 End-to-end network/application analysis methodology Short term goal: structured process Long term goal: automated analysis Network performance within multi-core computing systems Process scheduling, cache affinity, interrupt affinity Parallelism, scalability Current Research Projects

5. 5 End-to-end Network/Application Performance Analysis Methodology

6. 6 End-to-end network/application performance is viewed as Application-related problems Beyond the scope of any standardized problem analysis Host diagnosis and tuning Network path analysis Network performance analysis methodology Analyze and appropriately tune the hosts Network path analysis, with remediation of detected problems where feasible If network end system and network path analysis do not uncover significant problems or concerns, packet trace analysis will be conducted. Any performance bottlenecks will manifest themselves in the packet traces. End-to-end Network/Application Performance Analysis Methodology

7. 7 Publications Journals Wenji Wu, Mark Bowden, Matt Crawford, Phil Demar, “End-to-End Network/Application Performance Analysis Methodology”, In Review, IEEE Transactions on Parallel and Distributed Systems, 2007. Wenji Wu, Matt Crawford, “Interactivity vs. Fairness in Networked Linux Systems”, Computer Networks (Elsevier), Volume 51, Issue 14, pp. 4050 – 4069, 2007. Wenji Wu, Matt Crawford, “Performance Analysis of Linux Networking – Packet Receiving”, Computer Communications (Elsevier), Volume 30, Issue 5, pp. 1044 – 1057, 2007. Wenji Wu, Matt Crawford, “Potential Performance Bottleneck in Linux TCP”, International Journal of Communication Systems (Wiley), Volume 20, Issue 11, pp. 1263 – 1283, 2007. Conferences Wenji Wu and Matt Crawford, The Performance Analysis of Linux Networking–Packet Receiving, Proceedings of Computing in High Energy Physics (CHEP) 2006, Mumbai, India, 2006. Wenji Wu, et. al., End-to-End Network/Application Performance Troubleshooting Methodology, Proceedings of Computing in High Energy Physics (CHEP) 2007, Victoria, BC, Canada

8. 8 Network Awareness Lambda Station: A SciDac project for alternate path forwarding Compliments WAN end-to-end circuits But application awareness is hard New research area: network awareness of applications Detect recognizable flow patterns and modify path/service/whatever Based on “real time” flow analysis Testing very basic prototype now