The New Linux 3.0 Kernel -- Not Just a Numbers Game

Coinciding with the 20th anniversary of Linux®, Linus Torvalds made the numeric jump to 3.0 from the long line of 2.x kernels. Some say the new capabilities in the Linux 3.0 kernel aren’t worthy of the new number. Well, major number change, minor number change—what is important to remember is that creating a kernel for a commercial Linux, such as Red Hat® Enterprise Linux, is an exercise in integrating some of the best features from Linus' Linux kernels into a single product.

So, here is where Red Hat’s key value to customers comes in. Red Hat has a dual role of contributing to Linux kernel innovation coupled with providing its enterprise support distribution. Red Hat's engineering organization works closely with the Linux community, partners and customers to identify the right features and their degree of maturity for inclusion in Red Hat Enterprise Linux.

While Red Hat used the 2.6.32 kernel as the starting point when creating the Red Hat Enterprise Linux 6 kernel, it contains capabilities from all subsequent kernels as well as features from the 3.x kernels. Red Hat is able to do this through its unique methodology of back-porting new kernel features to the Red Hat Enterprise Linux kernel.

Standardizing on a core version for the lifetime of a Red Hat Enterprise Linux release is a fundamental feature of the product because it allows the maintenance of application interfaces (API/ABI) so applications are able to continue to run smoothly even as new features from later kernels are added. This interface stability benefits both customers and ISVs.

Often the integration of new kernel features and preservation of compatibility are opposing forces. Some Linux providers require their customers to “pick one” - features or compatibility. Red Hat has many years of successful experience in adapting new features to facilitate integration while maintaining compatibility. As a result, we believe that Red Hat Enterprise Linux kernels are unique in the industry in their ability to preserve compatibility through feature integration. This requires the substantial effort and skill that Red Hat is well-equipped to deliver to customers.

There are several new capabilities in Red Hat Enterprise Linux 6.1 gleaned from the Linux 3.0 kernel:

• Driver additions and updates to support some of the latest hardware from leading hardware and platform providers;
• Virtual Memory and scheduler changes for improvements in virtual memory and process scheduling for faster and more reliable performance;
• Transparent HugePage enhancements that benefit large page application users; and,
• DUP tx lock scaleability improvements to increase DNS query per second performance.

Three key virtualization features from the Linux 3.0 kernel are incorporated in Red Hat Enterprise Linux 6.1:

• Kernel Samepage Merging (KSM) scanning into THP provides memory de-duplication for hosts to share pages for various virtual machines;
• Enhanced support for vhost-networking; and,
• FPU caching for KVM allowing virtualized guests direct access to floating point registers.

The bottom line? Red Hat's engineers are among the leaders in upstream kernel innovation and incorporate many of the latest and greatest features into the Red Hat Enterprise Linux kernel while protecting application interfaces over the long haul. This is what fundamentally makes Red Hat Enterprise Linux the world's most successful commercial open source operating system.