Linux Weather Forecast

Welcome to the Linux Weather Forecast.

This page is an attempt to track ongoing developments in the Linux development community that have a good chance of appearing in a mainline kernel and/or major distributions sometime in the near future. Your "chief meteorologist" is Jonathan Corbet, Executive Editor at LWN.net. If you have suggestions on improving the forecast (and particularly if you have a project or patchset that you think should be tracked), please add your comments to the Discussion page. There's a blog that reports on the main changes to the forecast. You can view it directly or use a feed reader to subscribe to the blog feed. You can also subscribe directly to the changes feed for this page to see feed all forecast edits.
Forecast Summaries

Current conditions: the 2.6.34 kernel was released on May 16. This development cycle was a little less active than its predecessors; it featured some 9,100 individual changes from just over 1,100 developers. As with 2.6.33, about 180 companies were identified as having contributed to this release; see this article for details on where code for 2.6.34 came from.

Some of the more notable changes in this release include:

* Asynchronous suspend and resume: a feature which will make it easier for systems to suspend peripherals which are not currently in use, saving power in a range of systems from embedded gadgets through to large data centers.

* More enhancements to the rapidly-developing tracing and performance events monitoring subsystem within the kernel. Dynamic tracing has gotten more flexible, there is a new facility for monitoring lock contention, and support for Python scripting has been added.

* The "vhost_net" interface will enable higher I/O performance for virtualized guest systems.

* The "VGA switcheroo" feature will allow Linux to make full use of systems with more than one built-in graphical processor.

* The LogFS filesystem has been merged; LogFS is intended for use on solid-state storage devices.

* The Ceph distributed filesystem, a high-performance filesystem intended to scale into the petabyte range.

Near-term forecast: the 2.6.35 kernel can be expected sometime in early August. The merge window for this release has now closed, so we can talk with confidence about the features that will be included. Some of the most significant are:

* The receive packet steering and receive flow steering mechanisms have been added to the networking subsystem. These technologies (contributed by Google) will help improve high-end network scalability.

* The memory compaction patch set has been merged. This should lead to less memory fragmentation and higher success rates for large allocations while improving memory management performance.

* The cpuidle "menu" governor now features idle pattern detection which tries to be smarter about sleep-state selection based on recent system history.

* The rapidly-developing Btrfs filesystem now has basic direct I/O support.

As I had predicted, it's a relatively unexciting development cycle with regard to new features. That doesn't mean that not much is going on, though: over 8000 changes went into the mainline during the merge window. We're seeing a lot of internal cleanup and improvement, but not a great many features at the moment.

The current development release is 2.6.35-rc6, released on July 22. If all goes well, this might be the last prepatch before the official 2.6.35 release.
Specific Areas of Interest

The forecast has been divided into a number of specific subject areas.

* Core Kernel Developments: schedulers, real-time support, event management, and memory management.
* Virtualization and containers: Xen, KVM, control groups, etc.
* Filesystems: ext4, btrfs, and other ways of storing data.
* Security: technologies and enhancements for keeping Linux systems secure.
* Networking: Network channels and other technologies for connecting systems together.
* Hardware Support: Topics of interest in hardware support.
* Miscellaneous: Topics which do not fit under any other heading.
* User Space: user-space code which forms an important part of the low-level platform.