Processor-hungry

1. Is it a known issue that the GNU/Linux client is very much processor-hungry? 2. Is it being worked on?

I notice this as well, my processor is constantly pegged at 100%

It's not a bug, it's a feature!

Seriously, most games (or game-like application, in this case) are pretty processor-intensive. And it throttles back when something else wants the proc. After all, your cycles are being wasted if they aren't getting used

Check the Windows client... similar proc usage characteristics. If SL used any less processor, it would lag even more

Like Darkside said, this is a common feature on most graphically intensive games (and these days, that's practically all of them) for any operating system. It's by design: the game will deliver the best possible framerate because it is throwing information at the screen as fast as it can.

If you've got some concerns that other applications of yours aren't going to get needed system resources, do some testing. I've run system upgrades in the background and, while they run a bit slower thanks to SL's network and CPU useage, they worked just fine.

You can try the following to give the system a little breathing time:

./secondlife -cooperative 50

50 here is just an estimate. Increase the value to take more time away from SL. The nature of this command causes a loss in frame rate, so the cure might be worse than the "disease".

Well, I'll try that out soon, because I have alot of stuff that runs nice, and a smidge of breathing room would be AWESOME.

You can also nice it or renice it.

Games use 100% CPU because they don't include idle calls in their processing loops. The game very well might be doing nothing at all but looping, but unless it calls sleep() it'll never give up active timeslices (Linux will still force it to preempt and multitask but not cooperatively.) All games exhibit this behaviour, and I would never want a game maker to introduce sleep() calls into a game.

You can write a C program that pegs 100% cpu and does absolutely nothing but run an empty loop. It's very easy to do. Adding sleep() calls to a game would make it horribly laggy since any process could steal the game's timeslices. In general any "realtime" applications do this.