The ‘fast startup’ slides are interesting too. The ‘logoff & hibernate’ is the only real ‘new’ feature there afaics. It’s interesting to see terms used that have become passe in Linux like ‘cache prefetching’ and ‘parallel startup’.

interesting windows 8 leaked info. is a post from: codemonkey.org.uk

No related posts.

It’s always good to see success stories, though there are a number of takeaway points from his write-up. One obvious thing is that basically no distro gets JACK integration ‘just working’ out of the box. I’m not advocating it be started always (except maybe in a ‘multimedia production’ spin of Fedora maybe. After all, not every user is going to be an audio content creator. Regardless, a big step forward would be having it start on demand when programs that need it get launched for example.

Then there’s the real time kernel. I’ve back and forth’d in email with Peter Kirn CDM’s editor quite a bit recently about the rt kernel. It’s still a fairly large diff outside of the mainline kernel. This has made it hard to integrate into Fedora. We try to avoid packaging additional flavour of the kernel where we can avoid it, just due to the increased workload each build causes (increased buildtime, increased space on mirrors, increased bugs…) Also, it occasionally lags behind mainline by a few weeks, which means it’s not really feasible for rawhide.
Hopefully the -rt maintainers have a strategy for eventually getting all the remaining parts merged, but I don’t think it’s going to happen any time soon. Until then, people who need -rt will find themselves either patching it in themselves, and foregoing kernel support from their distro, or choosing a distro which chooses to package it.

Anyway, I found it an interesting read, and was expecting it to be a lot more “linux fails” than it was, and ended up being pleasantly surprised.

I’ve a number of other thoughts on Linux as a music creation platform, which I’ll go into another time, as this post is starting to ramble.

Linux Music Workflow: Switching from Mac OS X to Ubuntu with Kim Cascone is a post from: codemonkey.org.uk

No related posts.

The failure mode looks like this:

$ modprobe acpi-cpufreq
FATAL: Error inserting (/lib/modules/…/kernel/arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.ko): No such device

Not particularly informative. We don’t spit out anything helpful to dmesg either. So what is the cause of this problem?
In many cases, /proc/cpuinfo shows the cpu supports speedstep (the ‘est’ flag). The answer in nearly all of these cases is.. The BIOS. The ACPI tables in the BIOS list which P-states a particular CPU supports. If your CPU was manufactured after your BIOS was written, you’re probably going to be out of luck. Sometimes, there are BIOS updates on the motherboard manufacturers website that will add support for newer processors. Sometimes we aren’t so lucky. In these cases, we’re out of luck, there’s nothing we can do.

There is another possibility for the error message above: kernel bugs. We have introduced bugs in the ACPI interpretor in the past which have broken parsing of the P-states on some platforms. These kinds of bugs tend to get noticed very quickly, and fixed in equally short time, but it’s worth making a point that it’s important to be running on the last kernel version before reporting bugs.

When acpi-cpufreq fails. is a post from: codemonkey.org.uk

No related posts.

Some of them are extremely processor intensive, especially as more and more voices get used. To mitigate this, some innovative people have decided to offload these, and other instruments to dedicated hardware.

The really awesome part, is that this hardware runs Linux. The hardware doesn’t seem to be anything too exotic. It’s basically just a decent spec PC in a rack-mount case, with an LCD and some knobs, and probably a decent sound card with a boatload of input/output connectors.

For example, Muse-Machine is built on top of Linux, the “industrial strength” operating system that is used by many of the world’s largest companies to run their servers, and the operating system that powers much of the Internet. Additional advantages that come from Linux include far more efficient memory usage, consuming as little as 5% of the available RAM compared with as much as 40% with other operating systems.

I’m not entirely sure how it all works. Maybe running them under wine? But it is pretty cool to see Linux penetrating a field almost completely dominated by Mac/Windows. I suspect there’s actually a lot more Linux in high end audio gear, but not all manufacturers are as smart as Muse and don’t think of marketing it as a feature.

All really neat stuff. Like most high-end pro-audio gear though, these things don’t come for cheap.Even the previous generation is over $2k.

A few days ago, Justin Forbes tipped me off that the 64studio people also got the NI apps working in Linux. Neat stuff. Still a lot of hoop jumping to get it all working, but a great step forwards for music production on Linux.

Pro audio apps and Linux. is a post from: codemonkey.org.uk

Related posts:

1. Linux Music Workflow: Switching from Mac OS X to Ubuntu with Kim Cascone Create Digital Music has an interesting post up today by...

The thing is, they never could.

From a recent posting to the cpufreq list:

I have a laptop (ASUS W7J) with an Intel Core2 T7200 2GHz.
…
When I use the p4-clockmod, I get:

available frequency steps: 250 MHz, 500 MHz, 750 MHz, 1.00 GHz, 1.25 GHz, 1.50 GHz, 1.75 GHz, 2.00 GHz
…

For every one of those ‘frequency’ options, the CPU is actually running at 2GHz. It never changes speed. Not at all.
The p4-clockmod driver abuses the cpufreq interface to expose a clock modulation feature that has been in processors for a long time. (Even the earlier pentiums had a variant of it). The driver modulates the clock applied to the processor so that instead of every clock cycle meaning the processor gets do some work, only a percentage of the clocks make the CPU do real work. The remainder of the time, the processor just sits there.

So the 1.00GHz ‘frequency’ is actually “run at 2GHz, but only do work 50% of the time”.

On the surface, this sounds like a good idea. The other 50%, the CPU is idle, so you’re saving power, right?
Not so much. In fact, you could be burning more power. The reason for this is that when the processor is sitting there doing nothing, it isn’t lower frequency, and more importantly, it very likely isn’t entering C states. So you’re burning the same amount of power, but now you’re only doing work for 50% of the time. As a result of this, your workload takes twice as long to complete.

If it isn’t saving any power, what is the point of this at all ?
A clue is revealed by reading the Intel programmers guide for this feature; it’s closely tied to the processors thermal monitoring feature. The idea of this feature is that when the CPU overheats, it can ‘back off’ a little, to prevent overheating. The temperature of a processor isn’t constant. When running flat out, it will generate more heat. So by modulating the clock, the maximum amount of heat possible to generate decreases.

The changes merged into the 2.6.29rc kernel remove the user-visible interface, and replace it with direct calls from the ACPI code that gets triggered on thermal events. It’s all entirely automatic now.

Forthcoming p4-clockmod changes. is a post from: codemonkey.org.uk

No related posts.