Linux Kernel 2.6.32 Released

diegocg writes "Linus Torvalds has officially released the version 2.6.32 of the Linux kernel. New features include virtualization memory de-duplication, a rewrite of the writeback code faster and more scalable, many important Btrfs improvements and speedups, ATI R600/R700 3D and KMS support and other graphic improvements, a CFQ low latency mode, tracing improvements including a 'perf timechart' tool that tries to be a better bootchart, soft limits in the memory controller, support for the S+Core architecture, support for Intel Moorestown and its new firmware interface, run-time power management support, and many other improvements and new drivers. See the full changelog for more details."

Comments

Llacking in terminology.

[c0l0]

I'm not perfectly happy with the term "virtualization memory de-duplication". Linux 2.6.32 introduces what is called "KSM", an acronym that is not to be confused with "KMS (Kernel Mode Setting)" and expands to "Kernel Samepage Merging" (though other possibilities with similar meaning have already emerged). It does not target virtualization or hypervisors in general (and QEMU/KVM in particular) alone. KSM can help save memory for all workloads where many processes share a great lot of data in memory, as with KSM, you can just mark a region of memory as (potentially) shared between processes, and have redundant parts of that region collapse into a single one. KSM automagically branches out a distinct, exclusively modified copy if one of the processes sharing those pages decides to modify a certain part of the data on its own. From what I've seen until now, all that's needed to have an app benefit from KSM is a call to madvise(2) with some special magic, and you're good to go.

I really like how Linux is evolving in the 2.6 line. Now if LVM snapshot merging really makes it into 2.6.33, I'll be an even more happy gnu-penguin a few months down the road!

Re:Llacking in terminology.

[Bert64]

I have a system running a 2.6.32-rc6 kernel with KSM and the latest kvm (which includes support for this, but its turned off by default)... Because i run a number of virtual images that boot the same kernel and system libs (different apps ofcourse), it saved me over 1gb of memory on the host.

Does it Fix XKCD 619?

[sheepweevil]

All of these features are cool and all, but does it solve the well-known XKCD 619 bug?

Re:Does it Fix XKCD 619?

[Anonymous Coward]

http://imgur.com/73EAu - RESOLVED, FIXED quite a while now!

Big speedups for media workstations..

[delire]

This 'Per-backing-device writeback' is pretty significant. I'm sure the feature film and database industries will love it especially:

The new system has much better performance in several workloads: A benchmark with two processes doing streaming writes to a 32 GB file to 5 SATA drives pushed into a LVM stripe set, XFS was 40% faster, and Btrfs 26% faster. A sample ffsb workload that does random writes to files was found to be about 8% faster on a simple SATA drive during the benchmark phase. File layout is much smoother on the vmstat stats. A SSD based writeback test on XFS performs over 20% better as well, with the throughput being very stable around 1GB/sec, where pdflush only manages 750MB/sec and fluctuates wildly while doing so. Random buffered writes to many files behave a lot better as well, as does random mmap'ed writes. A streaming vs random writer benchmark went from a few MB/s to ~120 MB/s. In short, performance improves in many important workloads.

Is this a hoax, or what?

[Sockatume]

rewrite of the writeback code

So you didn't de-lace the interace or uncabulate the turboencabulator? I'm now about 85% convinced that the open source movement is just making shit up.

People work on the "easy" problems

[Fished]

Like the strip, and it raises a valid point. The bottom line is that kernel development advances more quickly than user interface and applications for the same reason that physics advanced more quickly than say ... psychology. That is, because developing a faster kernel is a much easier problem than developing a fun, usable desktop environment. It's easier to write, easier to test, and easier to debug. People tend to gravitate towards problems that they think they can solve--and ignore the problems they don't understand or don't want to deal with.

Personally, I think that the best way forward for Linux on the desktop would be to take GNUstep to the next level. There's a LOT of code there already written, and with a bit more work you might be able to have source-level compatibility with Mac OS X--which would give you access to a bunch of commercial apps. And, most importantly, the ability of the OpenStep API to produce a world class desktop--best in the world in fact--is proven. After 10 years, I don't think that either KDE or GNOME have really done all that much for Linux on the desktop... it's time to try a different approach.

Of course, I'm just kibbitzing, not bringing code. So what right do I have to say anything?

Re:People work on the "easy" problems

[shutdown -p now]

That is, because developing a faster kernel is a much easier problem than developing a fun, usable desktop environment.

I disagree, it's not an easier problem. It is, however, a much more interesting problem to solve, especially to skilled hackers.

One other aspect here is that the target audience is bigger for the kernel. Desktop uptake is still very low, but kernel is used by any device that runs Linux, whether it's a router, a smartphone, a server, or a netbook. This has a side effect of kernel hacking being better financed than desktop development, as there are more commercial players interested specifically in the kernel, who couldn't care less about KDE or Gnome.

Re:People work on the "easy" problems

[bcmm]

You're missing the bit where Flash is closed-source and the people that want it to work properly can't make it happen, whereas the people who can make it work don't want it to happen.

Re:People work on the "easy" problems

[Hatta]

Making a good desktop environment is extremely challenging, as shown by the fact that no one has made one yet.

Re:Btrfs: kill off ext# please!

[Jack Malmostoso]

ReiserFS was set to kill them off, but unfortunately found another victim first

Too soon!

Re:does KSM mean the death of Xen?

[1s44c]

If KSM puts the KVM module on par with Xen in terms of performance then I think the writing is on the wall for Xen's demise.

No. Not at all. KSM saves memory but hurts performance. It shares memory across virtual machines to save memory.

Xen can't share memory across virtual machines, it's just not put together like that.

Performance is about identical for KVM and XEN.

KMS

[shentino]

Kernel Mode Switching is great except for the fact that all 3 major video card vendors decided to nix VGA console support.

Re:ATI support

[Anonymous Coward]

The 2D specs were released in September 2007. The 3D specs were released in January 2009. Drivers do not write themselves immediately just because the specs are out, it still takes some time. But it's getting there, and they won't go away like the closed drivers will, the moment the manufacturer feels it's no longer profitable to maintain them.

Re:does KSM mean the death of Xen?

[Bert64]

Instead of storing multiple copies of the same data in memory, it stores a single read-only copy and points the others to it. If you try to write to it, it traps, creates a new read/write instance which is exclusive to you and then points you at it...

Shared libraries work in much the same way. Shared libraries been implemented pretty securely for many years now.

Comment removed

[account_deleted]

Comment removed based on user account deletion

time saving makefile

[inode_buddha]

I'm very interested in the new make target. Specifically, "make localmodconfig". It seems that this new target will check your current .config, and also check whatever modules are currently loaded. It then creates a new config file which only builds the modules you are currently using. This could be a great time and space saving, as opposed to building everything and the kitchen sink as distros tend to do. It gives you a fairly easy and sane way to truly tweak your kernel to fit your box, or script it to fit a whole bunch of non-similar boxes.

Re:time saving makefile

[bcmm]

That's sounds potentially very useful, but beware that if it works the way you're describing it, it could remove, for example, support for USB MSC if your USB stick wasn't plugged in when you did it.