I'm not sure where to put this post because it seems to concern many things. So here's the symptoms and things I've done.

First I upgraded the motherboard, processor, RAM, and power supply for speed. I am now running a core 2 duo processor.

I am also running Slackware 11.0, so I went ahead and installed the linux-smp-2.6.17.13 packages from "extra". This did not quite work properly. So then I decided to recompile the kernel. This also did not work quite work properly.

Everything appears to be running fine and everything boots up. I'm even using the system right now to type this. The problems have to do with some of the applications which include Amarok, Kontact, Kopete, K3B, kfmclient filemanager (you might know it as the "home" icon), etc. Firefox is fine. Konsole is fine. Java IDEs are fine like Netbeans and Eclipse. Open Office is fine. All server side services like squid, sendmail, tomcat, httpd, etc. are fine too.

I don't understand why a few of these applications have now decided to just not work anymore. They simply hang. Sometimes they end up as processes I can't kill. I'm not even so sure this is kernel related.

A couple of other things worth mentioning. Both cores are running properly and being used. Also, there are no stability issues. When I try to reboot (because it is the only way to get rid of the "defunct" zombie processes, I see transactions are being replayed from the journaling filesystem (which is reiserfs). I normally don't have transactions getting replayed when I do a normal shutdown. I suspect it is these rogue processes that are leaving the disk in a bad state. I am also running software raid 1 which has never give be any problems.

Any suggestions would be greatly appreciated. I've been Googling this for 2 days and found _no_ information. Thanks.

Poorly designed code is susceptible to failure with multiple processors. Been that way for-ever.
If I was suffering I'd use cpusets to limit everything to one core and do some testing - them post a bug report if appropriate..

Amarok, Kontact, Kopete, K3B, kfmclient filemanager

Am using all these programs on smp without any problems

True I only have a single core with hypertreading.

Are you sure that it is related to cpu/kernel?

Maybe it's a disk issue

syg00,
Can you clarify what "cpusets" is. How would I use that to limit everything to one core without compiling a non-smp kernel?

x_terminat_or_3,
No I'm not sure it's related to the cpu/kernel. But that is the biggest change that was made to the system in my opinion. The rest is pretty generic stuff.

I was thinking about trying to recompile a kernel anyway so that it only used one core. I just want to see if that made any difference. I don't know what else to do? I'm completely stumped on this one.

Anyone else with some experience along these lines?

Thanks for all the replies. Things deteriorated more since my last post. The system wouldn't even boot up! It would almost boot up and then die as soon as the X server was almost up. I couldn't get in there in time to disable the X server. I tried swapping video cards again and again. Nothing was working. Very disappointing after spending nearly $500 on upgraded hardware!

Good news is.... Things are fixed! I had no other choice but to boot from rescue media. I found an old bootable Slackware 10.2 CD I had made for just such an occasion. I ran reiserfsck on all the partitions. I was suspicious because of the replayed transactions I was getting even after doing a clean shutdown.

Sure enough. I had a couple of corruptions. I reran it again with the --fix-fixable option. Then I did one last regular check. Things looked good. The system came right up. Everything appears to be functioning again!

This is the first time *ever* in the *many* years I've been using Reiserfs that I've ever I had a corrupted file system. I suspect with all the work I was doing with kernel recompilations, hardware changes and hard shutdowns, that the filesystem was damaged.

Thanks for the suggestions. Maybe this thread will help someone else who runs into some similar set of circumstances and symptoms.

Just as I suspected: a disc issue.

Glad you was able to sort it

Yeah, also glad you got it sorted.
cpusets is a means of partitioning your box along CPU boundaries - see ../Documentation/cpusets.txt.
Haven't played with a core duo, but it works as advertised on my 4-way Xeon. If I want to test CPU intensive (or loopers), I limit all processes under my id to specific processor(s).
Works a treat.
As I said, haven't tried a core duo, but can't see why it wouldn't work.

To see if cpusets is available, grep your kernel config.