Gentoo Linux Reloaded
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A Modern, High-performance Kernel

Gentoo Linux 1.4 also contains a new high-performance kernel for x86 systems. Some of our users prefer running stock, -ac, Red Hat, or Mandrake kernels, which are also fully supported. In fact, we provide ebuilds for vanilla and Red Hat kernel sources as a convenience for our users. That said, many have come to appreciate the Gentoo-sources kernel, which includes several patches to improve performance, scalability, functionality, and hardware compatibility.

Our new kernel is based upon 2.4.19 and includes Robert Love's preemptive kernel and scheduler-hints patches, Ingo Molnar's O(1) scheduler and smptimers patches, and Rik van Riel's reverse mapping patches, for enhanced responsiveness and scalability under high loads and in high-end multiprocessor systems.

We provide IBM's EVMS (Enterprise Volume Management System) support. EVMS is an excellent storage management system providing a single modular API that supports nearly all of Linux's storage technologies. You can find out more about IBM EVMS at the EVMS SourceForge site.

Related Reading Running Linux By Matt Welsh, Matthias Kalle Dalheimer, Terry Dawson, Lar Kaufman

The kernel contains extensive filesystem technology support including ext2, ext3, ReiserFS, XFS LVM, software RAID, JFS and EVMS. In addition to kernel support, Gentoo Linux's new LiveCD supports using all these storage technologies during the initial installation process, so that configuring your system to have a root EVMS or XFS filesystem is fully supported.

The new Gentoo Linux kernel also includes Andrea Archangeli's excellent 3.5GB user address space patch. This patch allows users to customize how Linux divides the system's user and kernel address space. Normally, there is a 3-to-1 ratio between user and kernel memory. A 32-bit Linux kernel thus can only "see" up to 960MB (~1GB) of RAM, with user processes accessing up to 3GB of virtual memory. By using a 3.5U/0.5K or 2U/2K divide, users can choose a balance that better suits the intended use and hardware configuration of their system. For example, a 2U/2K divide will allow a 32-bit Linux kernel to "see" 1960MB of RAM (~2GB) even without enabling "highmem" support. Alternately, a 3.5U/0.5K split plus highmem support can allow VM-hungry applications to access up to 3.5GB of virtual memory while still allowing (thanks to highmem) access to multiple gigabytes of physical RAM. This patch is tremendously helpful for developers who push 32-bit systems to their limits. This patch is also invaluable for those writing applications that need to access more than 3GB of virtual memory. For those interested in trying out this patch, you can find it in one of the kernel directories at http://www.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/.

There are several other miscellaneous features, such as the grsecurity security system, the excellent HTB3 QoS code, gcc-3 support, and a handful of various hardware compatibility tweaks (SiS 740/961 chipset support, Pentium 4/Xeon hardware detection fixes, and some VIA chipset fixes). NFS TCP support and updates and the FreeS/WAN IPSec implementation will also be popular.

Portage Improvements

The Portage system has been improved extensively since the 1.2 release, especially in its performance. By using extensive internal caching and external metadata caching, the new profiler-optimized Portage is now up to 100 times faster in common, day-to-day use. Here is a comprehensive list of additional major improvements since the Gentoo Linux 1.2 release:

• Enhanced searching with description searching support
• Keyword-based masking
• Improved config file protection
• Transparent ccache support
• Dependency caching for db-speed metadata retrieval
• Server-side cache entry generation for no cache population delay
• Extensive internal caching
• Enhanced local sandbox technology
• Enhanced dependency syntax ("||" and "? :")
• New "repoman" QA tool
• New Portage database API
• db "melting" and "freezing" for enhanced performance and flexibility
• Preliminary Portage tree overlay support (for local Portage trees)
• Overall orders of magnitude speed improvements
• New "global db update" framework for transparent upgrades

New "LiveCD"

Gentoo Linux 1.4 features a new "liveCD" installation CD that will boot into a full runtime version of Gentoo Linux. Because of this, this CD not only serves as an ideal platform for installing Gentoo Linux, but also makes an ideal rescue/repair CD and portable Gentoo-Linux-on-a-CD system.

The CD provides a full suite of Linux tools and a familiar Gentoo environment with near-zero RAM overhead thanks to tmpfs. Tools on the CD include fdisk, ext2, ext3, XFS, ReiserFS filesystem tools, EVMS tools ("evmsn"), parted, and many, many more.

And a "GameCD"

To promote accelerated OpenGL gaming under Linux, we used our LiveCD as the foundation for a fully self-hosted GameCD featuring the Unreal Tournament 2003 Demo. Our Unreal Tournament 2003 Gentoo LiveCD allows you to play the Unreal Tournament 2003 Demo using any modern PC with an NVIDIA GeForce 2 or greater graphics card and a CD-ROM drive. It has full networking, complete OSS sound support, and additional Creative Soundblaster Live! and Audigy support included, allowing for the full gaming experience including LAN/Internet play, EAX environmental audio, and 3D accelerated OpenGL graphics. Weighing in at approximately 220MB, the CD also serves as a fully-functional Gentoo Linux installation CD. If you're interested in trying our our GameCD, the best way to do so is to visit our FreshMeat.net GameCD page and download the most recent version listed there.

Accelerated OpenGL gaming (Unreal Tournament 2003) on the GameCD

The Unreal Tournament 2003 Gentoo LiveCD is an ideal way to play Unreal Tournament 2003 on network machines that are normally used for other tasks, such as in computer labs and offices after hours. We plan to refine our ut2003 CD, developing it into a full-fledged Linux gaming platform. It's a great way to promote the use of Linux and Linux gaming in general.

Extensive Updates to Portage

Gentoo Linux 1.4 also includes countless improvements to our Portage tree, the repository that houses all our ebuild scripts. Currently, we have over 2400 ebuild scripts, including full support for GNOME 2, KDE 3.0.3 and 3.1-beta1 (possibly 3.1 if it's ready), and XFree86 4.2.

That's it for this article. In the next article join me as we take an inside look at Gentoo Linux 1.4. See you then :)

Resources

Learn more about Gentoo Linux at http://www.gentoo.org/.

View the Gentoo Linux Social Contract.

Read a tinyminds.org interview with Daniel Robbins.

View screenshots of other Gentoo Linux users and developers.