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UW Operating Systems
  Systems Seminar

Spring 2012

The operating systems seminar is held every other Monday afternoon from 4:00 - 5:00 PM in Computer Sciences & Statistics room 2310.

Keeping up-to-date with current research is a critical task for both students and faculty. A weekly seminar is a fun and social way to keep in touch with other's work. At the seminar, you can eat a few cookies, chitchat about the finer points of mutual exclusion, and exchange ideas with students and faculty working in your field. The seminar schedule is a mix of original research being carried out at the University of Wisconsin, visitors to our department who will update us on their work, and short presentations and discussions led by current UW students of current operating systems papers.

To subscribe to our mailing list, please visit the mailman page at https://lists.cs.wisc.edu/mailman/listinfo/os-seminar The list traffic is about one or two messages per week to announce the next seminar, and the occasional newsworthy item about operating systems. Questions about the seminar and arrangements may be directed to Guoliang Jin (aliang @ [thisServer]).


Topic and Speaker
March 12
12:00 PM
2310 CS
Getting a Million IOPS Through Code You Don't Own
Bhavesh Mehta and Vikram Joshi Speaker

Abstract: Virtualization has brought in disruptive change to the way we use compute servers allowing for greater consolidation ratios, reduction of capital expenses and energy costs, and ease of IT management. But along with the benefits have come some serious challenges, the biggest one being the I/O bottleneck for virtual machines. Most hypervisors require the use of shared storage. While the I/O demands of any single VM may not be great, the aggregate I/O requirements of many VMs running on a single server quickly add up. Primary storage vendors have been the beneficiaries and monetized this surprise blessing that landed on their laps. Flash memory has changed the way we can look at both the I/O as well as the virtual memory subsystem of operating systems, allowing us to use Flash as a part of the new memory to storage hierarchy. The ability to use Flash transparently in compute servers to offload hundreds of thousands of IOPS from primary storage is now theoretically possible but still a daunting task given the idiosyncratic nature of the Flash medium and the need to seamlessly and transparently modify commercial/proprietary operating systems to deal with high I/O loads. This talk gets into the inner workings of unifying the memory I/O subsystems of OS-es to open up the flood gates

BIO // Vikram Joshi Vikram is a VP & Chief Technologist at Fusion-io. His technical background spans multiple disciplines such as operating systems, parallel and distributed systems, databases, storage, media and computer graphics. Prior to co-founding IO Turbine (acquired by Fusion-io), he founded PixBlitz Studios which developed high-definition virtual advertising technology for broadcast sports and entertainment. At Oracle, his work included doubling database performance on 12-64 way SMPs and laying the foundation for the Exadata appliance group. Vikram pioneered high-speed texture-mapped graphics for video, worked on video on demand, and video game server (CosmoSoft) at Silicon Graphics. At Sun Microsystems, he worked on the Solaris virtual memory subsystem to increase scalable OS performance up to 10X, and on the Spring Microkernel (Sunlabs). He holds a MS (Hons.) in Physics and a BE (Hons.) in Engineering from the Birla Institute of Technology and Science, Pilani, India.

BIO // Bhavesh Mehta Bhavesh Mehta is a software engineer at Fusion-io, working in kernel group solving interesting problems spanning storage and virtualization. He received his Master's from the University of Wisconsin in 2005 and worked in the Multifacet research group as a graduate student. Prior to joining Fusion-io he was a software engineer in the Hypervisor Group at VMware, where he contributed to wide range of features like monitor, vmkernel, EFI, fault-tolerence

May 7
11:00 PM
4310 CS
The Implications of Non-Volatile Memory on Software Architectures
Nisha Talagala

Abstract: Flash based non volatile memory is revolutionizing data center architectures, improving application performance by bridging the gap between DRAM and disk. Future non volatile memories promise performance even closer to DRAM. While flash adoption in industry started as disk replacement, the past several years have seen data center architectures change to take advantage of flash as a new memory tier in both servers and storage. This talk covers the implications of nonvolatile memory on software. We describe the stresses that non volatile memory places on existing application and OS designs, and illustrate optimizations to exploit flash as a new memory tier. Until the introduction of flash, there has been no compelling reason to change the existing operating system storage stack. We will describe the technologies contained in the upcoming Fusion-io Software Developer Kit (ioMemory SDK) that allow applications to leverage the native capabilities of non-volatile memory as both an I/O device and a memory device. The technologies described will include new I/O based APIs and libraries to leverage the ioMemory Virtual Storage Layer, as well as features for extending DRAM into flash for cost and power reduction. Finally, we describe Auto-Commit-Memory, a new persistent memory type that will allow applications to combine the benefits of persistence with programming semantics and performance levels normally associated with DRAM .

BIO: Nisha Talagala is Lead Architect at Fusion-io, where she works on innovation in non volatile memory technologies and applications. Nisha has more than 10 years of expertise in software development, distributed systems, storage, I/O solutions, and non-volatile memory. She has worked as technology lead for server flash at Intel - where she led server platform non volatile memory technology development and partnerships. Prior to Intel, Nisha was the CTO of Gear6, where she developed clustered computing caches for high performance I/O environments. Nisha also served at Sun Microsystems, where she developed storage and I/O solutions and worked on file systems. Nisha earned her PhD at UC Berkeley where she did research on clusters and distributed storage. Nisha hold more than 30 patents in distributed systems, networking, storage, performance and non-volatile memory.

Archive of Old Talks

Instructions to Speakers

  • Two weeks before your talk, mail a title and abstract to the seminar coordinators.
  • Plan to speak for forty-five minutes and answer questions for fifteen. (Shorter practice talks are also welcome.)
  • You may use whatever medium you prefer. We will provide a Linux/Windows machine, a digital projector, and an analog projector.
  • After your talk, mail a copy of your slides (.ps or .ppt) to the coordinators to be archived.
  • Speakers should bring cookies or a snack to share!
  • Suggestions for Giving a Good (or a Bad) Talk

  • by Mark D. Hill
  • by David A. Patterson
  • by David Messerschmit
  • by David Stock
  • by Bruce Donald
  • by Peyton et. al.
  • by Ian Parberry
  •   Maintained by Guoliang Jin and the OS faculty.