The next big upgrade of the Linux kernel, now known to be Version 2.6, will provide significant performance gains on higher-end machines as well as more responsiveness on the desktop. The kernel is expected to be declared stable by the middle of next year.
On the desktop, users should notice a smoother computing experience with the addition of two sets of patches: pre-emptible kernel patches and low-latency kernel patches. The two sets work together to provide greater responsiveness to user input (fewer mouse freezes when the system is under heavy load) and smoother multimedia playback.
On the server side, there are big changes coming in Linux. The entire memory allocation and disk subsystems have been redesigned for better performance and scalability.
The block I/O system and overall operating system disk cache are unified for better speed, and work has been done to remove locks in the storage code to allow a system to keep up with large disk arrays. Also new is a faster, more scalable process scheduler that doesnt get slower as the number of processes increases—Red Hat Inc. has already incorporated this piece into Red Hat Linux 8.0.
Asynchronous I/O and completion event APIs are new in the 2.6 kernel and provide ways for programs such as Web servers and databases to scale up without resorting to complex internal pooling mechanisms for network connections.
On the storage side, Linux 2.6 supports disks larger than 2 terabytes; on the file system side, were looking forward to using Silicon Graphics Inc.s XFS (Extended File System) enterprise file system. XFS may be the best new Linux file system for server use, especially in file systems that are hundreds of gigabytes or terabytes in size.
However, its not clear how supported file ACLs (access control lists) will be in the kernel, especially with the commonly used ext2, or second extended file system. We think ACLs are a critical enterprise feature that the Linux kernel needs to have.
On the security and administration front, user-mode Linux is an interesting addition. It allows a kernel and system image to be booted as a normal application, providing a great way to isolate a domain name server or Web server from the rest of the system.
West Coast Technical Director Timothy Dyck can be reached at firstname.lastname@example.org.
LINUX 2.6 KEY CHANGES
Faster, more predictable performance and new APIs are on tap
- Universal Serial Bus 2.0 and production Bluetooth support
- Pre-emptible kernel with low-latency kernel patches for more user responsiveness and better multimedia performance, even under heavy loads
- Updated I/O and memory subsystem for faster throughput and scalability
- Faster, more scalable process scheduler
- User-mode Linux to allow multiple system images running on the same box to aid server consolidation and application separation
- Asynchronous I/O and completion events—a big improvement for Web servers and databases
- Support for disks larger than 2 terabytes and for SGIs XFS enterprise file system
- Faster, POSIX-compliant threading library