muesli's Blog - Tech & Net

The X.org, NVidia & KWin Situation

nospam@example.com (muesli) — Mon, 12 Jul 2010 10:08:45 -0400

For months and months now, my Linux Desktop is suffering from one particular issue, which makes it a pain to use on a daily basis: After having it running for a few hours, suddenly X.org and KWin go bonkers and start eating up all my cpu horse-power.

It's not uncommon to see X.org spiking up to a whopping 60% CPU usage, followed by KWin using roughly another 25%.

Since I'm suffering from this issue now ever since I switched to KDE 4, I thought it's time to turn to you fellow KDE developers for some good advice, since all my undertakings to resolve the issue have failed:

I have tried to switch to a different / newer graphics card, experimented with various versions of the NVidia driver and tweaked X.org settings, have turned off various desktop effect plugins, switched between XRender and OpenGL, even re-installed Kubuntu on a new machine.

No dice, though... after it's been running for a few hours my desktop is completely unusable. Every mouse or keyboard action becomes sluggish, scrolling through lists takes ages and logging out from my KDE session up to two minutes (which is the only known way to resolve the situation, giving me another six hours or so, before I'll have to repeat that routine).

From talking on IRC, forums and a bit of googling I know that I'm not the only one who's having this problem. So I'm curious if anyone has experienced the issue and gained some insight as to what's actually going on. I'd be happy to know.

Update on July, 13th:
Still investigating and collecting data to figure out what's going on. Since I wrote this blog entry originally, my system suffered from terrible slowdowns twice more. In both cases X.org and KWin instantly stopped utilizing my CPU when I closed all GTK-based apps. (e.g. Firefox, Chromium, Pan, Gimp, ...)

At least this is some progress, even though I still don't know what might possibly be causing this. Running a pure Gnome installation, I've never experienced those issues.

Thanks,
Chris

Updating Web 2.0 Profiles Really Really Sucks!

nospam@example.com (muesli) — Wed, 04 Feb 2009 08:11:41 -0500

Don't you hate it? You've decided to take a new snapshot of yourself and update your avatar on... oh... Last.fm, Digg.com, Facebook, Twitter, MeinVZ.net, Lokalisten.de, everywhere. You have to go to every single website and change it manually. Changed your relationship status, phone number or discovered you can't stand your favorite movie anymore? There you go again. I don't even know how many websites I've signed up for now offer a twitter-like status update that I can't be bothered to use.

I'm kinda fed up with it.

I wish I could publish a standardized XML file on my webspace which contains all the data (like my Avatar, Current Status etc.), so all those Web 2.0 services could parse it and update my profiles automatically. There could even be a ping-back like mechanism where I tell the services when to check my XML for updates to avoid unnecessary traffic.

Now it would be easy to spec out such an XML and offer APIs to parse it in various languages. But I guess it would be daft to do so, since existing services don't even start to pick up on OpenID. After all, collecting this precious data is all those Web 2.0 services do and you don't want anyone to interfere with your core business, right?

Yet at the same time I feel like all those services would be able to gather even more data about me if they were able to import and sync my data with their profile.

(I'm aware that one would probably be able to write a Facebook application which could import the XML and update your profile. As long as Facebook is the only service to support this import mechanism, it wouldn't really help anyone, though.)

Update: It seems OpenID itself already supports avatar syndication. Read more about it here. (Thanks to Julian Stahnke for the link)

Mary Jo Foley embarrasses herself once more...

nospam@example.com (muesli) — Wed, 13 Jun 2007 03:05:51 -0400

Wow... Mary Jo Foley must be the world's dumbest techwriter. Or she was just really really drunk. For fuck's sake, I hope someone just hacked her account and wrote that article for her. Otherwise I hope ZDnet has some balls and finally shows this grandma the door. What happened? Well, if you enjoy a laugh, just go ahead, waste 5 minutes of your life and read her "Leopard looks like ... Vista" story.

Let me address and dismiss all of her points very quickly:

"1. New Leopard Desktop: Not a whole lot different from Vista’s Aero and Sidebar."

Well here's the first and biggest problem with you: You should be a designer, not a techwriter. You don't just judge features by their looks. Admit it, you just saw the desktop wallpaper, right? But you obviously missed the stacks for example. Besides that: Vista must be just like Windows 98 then. Still looks the same to me, after all.

"2. New Finder: Many of the same capabilities as the integrated “Instant Search” in Vista (the subsystem that Google is trying to get the Department of Justice to rule as being anti-competitive). The new Leopard Coverflow viewing capability looked almost identical to Vista’s Flip 3D to me."

Smart searches in Windows Explorer? Yeah right. You don't even know what a Smart Search is, right? And Flip 3D? The one which looks almost identical to something Apple introduced in iTunes before Vista came out, right? Wait a second, what was the name again? Ah yeah right, Coverflow it was called. Oh wait, but that would mean Vista just copied that from iTunes and not vice versa.

"3. QuickLook: Live file previews — just like the thumbnail preview capability available in Vista."

Sweetie, I don't believe you really attended the Keynote. Show me just one of the QuickLook features that Apple showcased in your beloved Thumbnail. Good luck finding them.

"4. 64-bitness: Leopard is the first 64-bit only version of a desktop client. Vista comes in 32-bit and 64-bit varieties. And most expect Windows Seven will still be available in 32-bit flavors. Until 32-bit machines go away, it seems like a good idea to offer 32-bit operating systems."

Again, I just don't understand how you ever got your job? Didn't people at ZDnet notice that you've actually just ran into the wrong interview and were supposed to become a gossip reporter? Almost all new computers you can get nowadays come with a 64bit CPU. (Intel Core2Duo e.g.). All Apple machines you can buy today are 64bit machines. And contrary to Windows you just boot up a 64 bit Leopard / Darwin kernel and are able to mix 32bit and 64bit applications in userspace.

"5. Core animation: Not sure what the Vista comparison is here. The demo reminded me of Microsoft Max photo-sharing application. The WWDC developers attending the Jobs keynote didn’t seem wowed with this functionality."

Oh my god. CoreAnimation is an API not an application. What they showed was just a demo, so developers get a clue what they can do with this Framework. This demo had nothing, not the slightest thing, to do with Microsoft Max photo-sharing. I bet this demo application won't even be shipped with Leopard, because anyone could write it in a couple of days with CoreAnimation. That was their entire point.

"6. Boot Camp. You can run Vista on your Mac. Apple showed Vista running Solitaire in its WWDC demo. But I bet those downloading the 2.5 million copies of Boot Camp available since last year are running a lot of other Windows business apps and games."

Well of course they are. What's your point, though? They just showed Solitaire to prove that Windows actually runs fine on the machine. Would you have wanted them to showcase all new Vista features at the Apple Keynote, too?

"7. Spaces: A feature allowing users to group applications into separate spaces. I haven’t seen anything like in in Vista, but the audience didn’t seem overly impressed by it."

Because the audience (developers, remember?) knew that since January already. Whereas your knowledge, once more, seems absent. Besides that it existed on Unix/Linux desktops since a decade... and I can tell you it's a damn good feature to keep your desktop clean and speed up your workflow.

"8. Dashboard with widgets. Isn’t this like the Vista Sidebar with gadgets?"

SIGH... I'm really getting fed up with you now. Where have you been the last ten years, god damn. Vista's Gadgets are a copy of Dashboard, which already existed since Tiger and came out long before Vista. They just improved it big time for Leopard... or where are the widget scissors in Internet Explorer?

"9. iChat gets a bunch of fun add-ons (photo-booth effects, backrops, etc.) to make it a more fully-featured videoconferencing product. The “iChat Theater” capability Jobs showed off reminded me of Vista’s Meeting Space and/or the new Microsoft “Shared View” (code-named “Tahiti”) document-sharing/conferencing subsystems."

I must admit, this time it's me lacking the knowledge - I never tried / seen Vista's Meeting Space. So let's give you a point here and just assume you're right (even though I bet you even cocked up this point and some commenter will be able to prove it).

10. Time Machine automatic backup. Vista has built-in automatic backup (Volume Shadow Copy). It doesn’t look anywhere near as cool as Time Machine. But it seems to provide a lot of the same functionality.

Backup applications like Vista's exist since the very first computer I ran (an ITT 3030 CP/M system) obviously and didn't improve much over the last 20 years or so. Again, I just can't believe you've seriously been watching the entire keynote. Otherwise you would have noticed Time Machine's seamless integration with the Finder and the way it logs 'states' and changes for every folder on the disk.

Mary Jo Foley, do us all a favour please and quit your job tomorrow. You seem to be resistant to technical knowledge, logic and truth, so just go ahead resign and stop this awkward embarrassment. Also your grand-children might not have to ask you why everyone's pointing and laughing at you in the future. It'd be a win-win really.

Kind regards,
Chris

Fight spam while digitizing books

nospam@example.com (muesli) — Fri, 25 May 2007 02:19:47 -0400

You know CAPTCHAs? Those annoying, weird, funky, little letters that you have to enter everywhere nowadays to leave a comment or sign up for an account. They're just there to prevent spamming and bots signing up, by verifying that you're a real human being.

Now, wouldn't it be nice if this annoyance would at least provide some benefit? That's exactly what reCAPTCHA is about. The difference to a normal CAPTCHA: it presents you two words instead of just one weird five-letter combination. The one word it already knows about and again, it is there to verify you as a real user. The other one, though, is a scanned picture from an old book which is currently being digitized, and the CAPTCHA system doesn't know what the word actually reads. But it's really easy for you to identify, so you help out by also entering the second word, which gets stored and helps recovering and digitizing old books. Awesome.

libketama - a consistent hashing algo for memcache clients

nospam@example.com (muesli) — Wed, 11 Apr 2007 05:39:59 -0400

We wrote ketama to replace how our memcached clients mapped keys to servers. Previously, clients mapped keys->servers like this:

server = serverlist[hash(key)%serverlist.length];

This meant that whenever we added or removed servers from the pool, everything hashed to different servers, which effectively wiped the entire cache. We add (and sometimes remove) servers from the memcached pool often enough to warrant writing this - if your memcached pool never changes, you can probably stop reading now

Ketama is an implementation of a consistent hashing algorithm, meaning you can add or remove servers from the memcached pool without causing a complete remap of all keys.

Here's how it works:

- Take your list of servers (eg: 1.2.3.4:11211, 5.6.7.8:11211, 9.8.7.6:11211)
- Hash each server string to several (100-200) unsigned ints
- Conceptually, these numbers are placed on a circle called the continuum. (imagine a clock face that goes from 0 to 2^32)
- Each number links to the server it was hashed from, so servers appear at several points on the continuum, by each of the numbers they hashed to.
- To map a key->server, hash your key to a single unsigned int, and find the next biggest number on the continuum. The server linked to that number is the correct server for that key.
- If you hash your key to a value near 2^32 and there are no points on the continuum greater than your hash, return the first server in the continuum.

If you then add or remove a server from the list, only a small proportion of keys end up mapping to different servers.

The majority of the code is a C library (libketama) and a PHP4 extension that wraps it. I've also included a class from our Java client. (Java Collections makes it rather easy). We use a single-server memcache client wrapped with a native php class to make it multi-server capable, so we just replaced the hashing method with a ketama_find_server call. (should be easy enough to plug this into libmemcache if need be)

http://static.last.fm/ketama/ketama-0.1.1.tar.bz2

We've been using this in production for all our PHP installs and Java services at Last.fm for around 10 days now. We deployed it just in time to smooth over moving loads of webservers between datacenters.

For further information, please refer to the README inside the tarball or these threads on the memcached mailing list:
http://lists.danga.com/pipermail/memcached/2007-April/003853.html
http://lists.danga.com/pipermail/memcached/2007-April/003834.html

VLC 0.9.0

nospam@example.com (muesli) — Wed, 07 Mar 2007 08:02:24 -0500

"Good news everyone", looks like VLC is going to ship with a Qt4-based GUI in the future. That means I can finally fix some issues with the clumsy VLC GUI, that annoyed me for so long on OS X.

I would imagine VLC could become the Qt4-project with the largest userbase shortly. A larger userbase results in a better product (usually), helping Trolltech ironing out bugs and finding out what developers really need. I really hope more projects are going to pick up Qt4 in the long-term for exactly those reasons.

...muesli

Why DOS uses backslashes instead of slashes.

nospam@example.com (muesli) — Mon, 12 Feb 2007 04:42:00 -0500

Larry Osterman tells the entire story: simply because slashes were already used for parameters before DOS even knew what a path or a directory is. Nice read and a trip down memory lane.

Reminder To Self

nospam@example.com (muesli) — Mon, 12 Feb 2007 01:25:50 -0500

If someone should ever tell you about MySpace code again, he actually means HTML. Also try to teach him not to double-click on links.

Just waiting for MyWeb 2.0 ...

Happy New Year

nospam@example.com (muesli) — Sun, 31 Dec 2006 14:17:52 -0500

Just wanted to wish everyone a Happy New Year. Keep on hacking and thank you all for your contributions to KDE this year. 2007 ought to be great

Now go and party till dawn!

Know C++, Maybe Even Love Qt4?

nospam@example.com (muesli) — Tue, 14 Nov 2006 17:38:12 -0500

Someone out there looking for a new job opportunity? Enjoy accessing a huge music-library? Even more important: always wanted a red user-icon on Last.fm?

There you go, start working at Last.fm as a C++ Developer. You will be working on the Last.fm Client, a Qt4-driven piece of software for Windows, Linux and OS X. Want more info? Click the link. It's worth it. Oh, and it's fun.

Now I wanna see you guys applying

cheers,
muesli

Sony GPS-CS1 - on its way

nospam@example.com (muesli) — Thu, 14 Sep 2006 04:03:49 -0400

Just ordered at sonystyle.co.uk: Sony GPS-CS1. So looking forward to this little device. It records your GPS position automatically every 15 seconds and stores it in memory. You can then just plug it into your computer and sync the positions with the images you took. Et voila: you end up with perfectly tagged images, that you can view on a (world-)map.

Oh by the way, even though Sony officially only claims it's compatible with CyberShot and other Sony cameras, I can assure you that it's actually compatible with any camera / JPEG files in general. When you plug in the device, you can simply mount it as a disc. You'll find proper NMEA GPS logs which you can import in most GPS mapping software.

Short specs:
- Runs on standard AA batteries (14h per battery).
- Capacity for aprox. 86.400 (360h) position records.
- Stores one record every 15 seconds.

New spiegel.de layout

nospam@example.com (muesli) — Thu, 07 Sep 2006 10:20:26 -0400

Yay, finally they did it. Love it so far. I never understood the disappearing side-menu anyways.

Is There One Sane DSL Router?

nospam@example.com (muesli) — Mon, 04 Sep 2006 08:05:13 -0400

Saturday night our DSL router died. The LEDs simply went off and even loud cursing and bashing against the wall didn't reanimate it. I'd like to forget about this piece of hardware as soon as possible anyways, so R.I.P Belkin. But please, never buy a Belkin router. I had to reboot mine every now and then, since I simply couldn't ping or reach it anymore. Also, the reallife bandwidth of this 54mbit wave-lan access point was a joke and competed with good old 10mbit coax.

So off to PC World and just get a new DSL router, right? That's what I thought. At first I came home with a shiny new Linksys WRT54GS. Luckily RJ discovered that a broadband router isn't necessarily able to connect via broadband before we opened the box. Their concept of broadband routing is to connect this Linksys to your DSL/Cable Modem - which we don't have. It was supposed to be in the router, that's why it's called broadband router. So back to PC World, returned the Linksys and bought a D-Link DSL-G624T. It features a real DSL-modem, that's the upside. It even runs a proper Linux kernel and BusyBox. That's another plus on my checklist. It even comes with proper QOS and ADSL2+ support. I'm impressed. But then it started... already the installation was weird.

First of all, half of the D-Link's web-interface is not functional with Firefox. It is slightly better with Konqueror and Opera seems to work for 90% of (the really extensive and featureful) web config. Seems to be a case of "Designed for Windows XP". Amusing when you know that it's driven by Linux But ok we got a Windows Notebook connected to it, so we managed to deal with it. Strangely enough we couldn't connect with any other wave-lan devices to it, yet the access control was disabled. After a few reboots of all our devices it suddenly started working. Fingers crossed. But guess what? This device, just as the old Belkin that died, starts randomly shutting down the wave-lan port every now and then as well. Oh the joy of rebooting.

Sigh.

Microsoft Photosynth looks impressive

nospam@example.com (muesli) — Mon, 31 Jul 2006 01:24:56 -0400

Photosynth is a software aiming at detecting and combining several similar photos to create a big 3D world. Pictures (or rather a vido in that case) speak more than a thousand words: Watch Microsoft Photosynth in action.

The software seems also to be able to find similar pictures to a given photo and even promises to automatically identify known objects on images of various different sources.

Battery died

nospam@example.com (muesli) — Sun, 30 Jul 2006 04:59:58 -0400

I just had my MacBook for a few weeks and now the battery already died. It won't power up without its power-adapter at all, and once it is running OS X just tells me "No batteries available". Seems I am not the only one.

Guess I got to go to the Apple Store tomorrow and ask for a quick replacement. I just hope I don't have to wait weeks for a silly new battery. First revision Apple products... what did ya expect.

sigh,
muesli

Update: Here's an official thread on apple.com about this issue.