Manic Depressive Processor

For a while my laptop has displayed an inconsistent yet highly annoying problem in Linux with the internal timekeeping mechanisms. It's manifested itself at seemingly random points ever since I got the laptop. I'm not sure whether it's something I haven't configured correctly in the kernel or whether it's a hardware thing. I've never seen the problem before in Windows, so I can only assume it's something I've (not?) done.

The problem is that the computer's internal clock seems to go completely haywire. The problem only used to trip off when I was doing large high-speed transfers over the network to/from other machines. At that point, the computer starts freaking out, and by looking at the system clock and other various time-based readouts, it seems to be going 5-10 times faster than it should be. Time based calculations such as bandwidth or disk transfer rates are divided by that same factor of 5-10.

When the transfer stops, the computer switches over to sloth mode, where each second ticking by on the computer corresponds to about a minute or more in reality. What is really strange though is that not everything slows down. Most interactions with X are still speedy. Switching desktops in fluxbox is still quick, the mouse moves at normal speed, and launching new terminals is zippy. Typing in those new terminals though, is not zippy. It takes around a minute for any keystrokes to show up in the window, and if you trigger a console beep for whatever reason, you'd better hope the sound is low, because that beep is going to be a constant force in your life for the next 2-3 minutes. It's a very annoying problem to say the least.

In the past week or so, since upgrading to a newer 2.6.10 series kernel, the problem has become much more frequent and shows less of a pattern. It just seems to come out of the blue whenever it feels like it. Sometimes I'm doing something on the laptop, sometimes it's just sitting there with the lid closed. Every time I've searched for this problem anywhere I've come up empty. The only thing I can think of that would cause this problem is some sort of screwup with the IRQ that controls the system timer. Unfortunately for me I'm not a kernel developer, so I'm not sure where to look first. I know that SMP-enabled kernels have some extra IRQ related juggling to do, so I figured I'd disable that first. My laptop has a hyperthreaded Pentium4, so the SMP stuff is actually used, but if turning that off fixes my problem, then it's off for good, or until someone else suggests something different. I'm working on an hour and a half of my laptop not being stupid, but I'm not sure if the problem is cured since I have no idea what triggers it. I guess I'll have to see.

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