Faculty Cand & CSE 600: Changwoo Min

Monday, March 6, 2017 - 14:30 to 16:00
Room 120 (105 Seats)

All are welcome!
CS Faculty Candidate & CSE 600 with Changwoo Min

Improving Filesystems for Reliability and Scalability

The file system is an essential component of any operating system. Since data is eventually stored and accessed by file systems, any reliability and scalability problems in file systems will have critical impacts. For better reliability, developers often rely on code checkers, such as Linux's Sparse. However, the capability of existing tools is limited to finding only shallow bugs without requiring deep semantic knowledge. Also, recent advances in many0core CPUs and blazing fast SSDs make fast, concurrent I/O operations feasible. Unfortunately, it is difficult to achieve scalability, since these file systems have hidden scalability bottlenecks that resurface for many I/O intensive applications even when there is no apparent contention at the application level.

This research aims to improve the reliability and scalability of file systems. In this talk, I will present my two recent works, Juxta and FxMark. Juxta is a static tool to find semantic bugs that are nearly 90% of all file system bugs. To find semantic bugs, Juxta compares multiple file system implementations and considers deviant ones as potential bugs. Using symbolic executions, Juxta found 118 previously unknown semantic bugs in 54 Linux file systems, many of which have been fixed based on our finding. Next is FxMark, which is a benchmark suite to evaluate the manycore scalability of file systems. To unveil hidden scalability bottlenecks, FxMark stresses the specific components of each file system. It has stressed five widely-deployed file systems and found 25 scalability bottlenecks, many of which are unexpected or counter-intuitive. It has also unveiled several core aspects of file system design that systems researchers must address.

Bio: Changwoo Min is a research scientist in Computer Science at Georgia Institute of Technology. He generally works in the area of operating systems and systems software. In particular, his focus is designing and implementing reliable and scalable file systems for the manycore architecture. His research discovered nearly 200 critical bugs in real-world software including the Linux kernel, and his algorithm and benchmark for scalability have been adopted by the Linux kernel community. His work has been published in top-tier systems conferences (SOSP, ATC, FAST, EuroSys, SIGMOD, and PACT) as well as other top-tier security conferences (USENIX Security). He received his Ph.D. degree from Sungkyunkwan University (in Korea) in 2014. Before starting his Ph.D., he developed various software products including Linux-based mobile platform (Tizen), Java virtual machine (J9), and desktop operating system (OS/2) in Samsung Electronics and IBM Korea.


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Faculty Cand & CSE 600: Changwoo Min