Linux Scalability Project
Status report for May and June, 2000
Center for Information Technology Integration
School of Information at the University of Michigan
The primary goal of this research is to improve the scalability and robustness
of the Linux operating system to support greater network server workloads more reliably.
We are specifically interested in single-system scalability, performance, and reliability
of network server infrastructure products running on Linux, such as LDAP directory
servers, IMAP electronic mail servers, and web servers, among others.
Summary
We're continuing to work with vendors such as Sun and IBM on their Linux scalability
issues. We've provided several significant modifications to the Linux kernel. We
attended the 2000 Usenix technical conference, and presented three papers. We're
continuing to reach out to potential sponsors. Work continues on long-term projects.
Milestones
- Stephen Molloy is spending his summer in Austin, Texas, interning at the
Austin IBM lab. Stephen is completing Linux scheduler work he started at CITI.
- Randy Appleton of Northern Michigan University was unable to join us this
summer. Chuck plans to implement the POSIX fadvise() system call in hopes that
Randy can analyze it at some future time.
- The NFSv4 project will complete at the end of August. A complete snapshot
release of the Linux NFSv4 implementation will be made available at this time.
Meanwhile, the project is preparing to participate in the July 12 bake-off.
Andy is working on file locking, while Kendrick completes support for delegation.
Jim Rees and Dug Song are preparing an OpenBSD port of NFSv4 for the bake-off
in July. Follow-on work is being pursued. See the NFSv4 project site for more
information.
- Niels, Chuck, and Stephen presented three papers in the Freenix track at
this summer's Usenix technical conference. See the Freenix track proceedings
for more information. While at the conference, CITI staff met with members of
the Linux kernel development community to discuss future research directions
and funding opportunities. CITI will increase its presense at upcoming conferences,
including the San Jose Linux Expo, ALS, and OLS.
- Niels' /dev/poll implementation has garnered praise and attention from the
Linux community. We are preparing a version of this work for inclusion in the
2.4 Linux kernel.
- Both paper submissions to October's Atlanta Linux Symposium were accepted.
One paper reports on our continuing study of POSIX RT signals, while the other
paper analyzes the performance of kernel hash tables.
- Chuck continues analyzing and improving phhttpd, a POSIX RT signals-based
server written by Zach Brown. This work will provide a better picture of performance,
scalability, and usability issues surrounding network server applications that
build their event core using POSIX RT signals. Zach has accepted Chuck's patches
into the phhttpd source distribution.
- Inessa is studying mmap() scalability issues. When many mapped objects exist
in an address space, mmap() slows down linearly looking for an unused address
for a new mapping. Benchmarks and solutions are in the works.
- Will Morris has agreed to replace Claire Hough as Chuck's Netscape manager.
Chuck plans to meet with Will and his boss, Stephen Borcich, in August to discuss
ways to move the project forward.
- CITI and LSP sponsors are assembling a one-day workshop on Linux network
server scalability issues of interest to researchers and industry. More news
to follow.
- We continue to pursue research relationships with Red Hat Software, Silicon
Graphics Incorporated, and the Stichting NLNet Foundation.
If you have comments or suggestions, email linux-scalability @ citi.umich.edu
Copyright 2000