What's New in Linux 3.3?

Sunday, Linus Torvalds released the 3.3 Linux kernel. In the latest installment of the continuing saga of kernel development, we’ve got more progress towards Android in the kernel, EFI boot support, Open vSwitch, and improvements that should help with the problem of Bufferbloat.

Is it just me, or is it still a little weird to be talking about 3.x kernels? It’s been about eight months since the official bump to 3.0, but that’s compared to more than seven years with the 2.6.x series.

At any rate, here we are. Let’s take a look at some of the changes in Linux 3.3!

Everybody was Bufferbloat Fighting!

The Android patches are likely to get the most attention in 3.3, but the thing that I’m most excited by? More work going on to solve the Bufferbloat problem.

In a nutshell, Bufferbloat is a symptom of a lot of small problems that creates “a huge drag on Internet performance, ironically, by previous attempts to make it work better. Or the one-sentence summary, “bloated buffers lead to network-crippling latency spikes.”

It’s not a problem that’s going to be solved all in one go, or in one area. But the Linux kernel is one of the pieces that needs addressing. In the 3.3 release, we’ve got the ability to set byte queue limits in the kernel.

Driver Goodies

Check out the list of drivers that have made it out of staging. Specifically, the gma500 driver is out of staging. This means the infamous Poulsbo chipset should be supported in the mainline kernel finally.

This release also includes the NVM Express driver (NVMe) which supports solid state disks attached to the PCI-Express bus. Most SSDs are SATA, Fibre Channel or SAS drives. The work was done by Intel’s Matthew Wilcox, which isn’t surprising since the NVM Express standard is also supported by Intel and a number of other companies. Would love to get my hands on one of these drives to test the 3.3 kernel out…

Want to tether your Linux box to your brand new iPhone? The iPhone USB Ethernet Driver (ipeth) module has been updated to add support for the iPhone 4S.

The 3.3 kernel also picks up some drivers for third generation Wacom Bamboo tablets and Cintiq 24HD, and initial driver support for the Intuos4.

Open vSwitch

Another biggie in 3.3? The Open vSwitch project is merging into the kernel tree. It’s not new – it’s been around for some time – but it’s finally making its way into the mainline kernel. (This seems to be a frequent theme, doesn’t it?)

Basically, Open vSwitch is a virtual switch for complex virtualized server deployments. Given the ever-growing popularity of virtualized servers and cloud deployments, this is something in high demand. As the Open vSwitch page says, “Open vSwitch can operate both as a soft switch running within the hypervisor, and as the control stack for switching silicon. It has been ported to multiple virtualization platforms and switching chipsets. It is the default switch in XenServer 6.0, the Xen Cloud Platform and also supports Xen, KVM, Proxmox VE and VirtualBox. It has also been integrated into many virtual management systems including OpenStack, openQRM, and OpenNebula.”

No doubt, you’ll be reading more about Open vSwitch on Linux.com in the near future.

Android Comes Closer

Last, but not least, the 3.3 kernel includes nearly complete support for Android. This is good news all around, but isn’t really a surprise. The kernel folks have been working on this for a long time.

Now the question is, will we start seeing Android apps on top of normal distributions? Will we start seeing standard Linux apps running on Android? Will mod communities, like CyanogenMod, start using the mainline kernel? Should be an interesting year. Then again, when isn’t it an interesting year when Linux is involved?

As usual, the release includes lots more fixes, new drivers, and so forth. Check out the Kernel Newbies page for more. The merge window for 3.4 is now open, with the traditional two-week cutoff for pull requests. Looking forward to what 3.4 brings!