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lundissimo · Jun 30, 2006, 05:42 PM

On a G4 PowerMac with dual 450MHz processors, when I run Activity Monitor cpu 2 is at 100% most of the time. In the time-progressive CPU bargraph, every once in a while (< 10 sec) cpu2 activity dips and cpu1 goes to 100% for a bit, then cpu2 goes back up. In the upper panel, displaying All Processes shows that its the kernel_task (PID 0) that's taking up all the juice. I am running OS X 10.3.9.

I've disconnected both FireWire devices (external HD & CD-R/W drive), as well as the USB printer and Audiophile interface, and disabled the network interface, same symptom. Either some hardware is interrupting the cpu frequently, cpu2 taking the interrupt as cpu1 is normally busy with normal stuff, or there might be some software problem.

I've considered upgrading to a Powerlogix cpu, which would eliminate the problem if it's originating on the cpu board - but if it's externally generated or software-related, this won't help.

Also, aware of problems with the disk controller chip on early G3's, I wonder if the controller on this G4 could be generating spurious interrupts.

Has anyone seen this type of thing, or have any ideas as to what might be causing it?

Thinine · Jun 30, 2006, 08:22 PM

Restart the machine and only launch Activity Monitor once you're logged in. If kernel_task is still taking 100%, that's a problem. If it's persistent, you may have something wrong with your install, so I would recommend reinstalling the system. If you can, wiping the drive and starting from scratch would be best.�

RealMac · Jul 1, 2006, 03:32 PM

For what it's worth, I have experienced the same issue on my MacBook Pro. Reinstalled, zapped the pram, reset the Power Manager. Haven't used the system long enough to see if the problem is stil there.

Phrogman · Jul 1, 2006, 03:53 PM

I've just noticed the same thing on my MDD 1ghz dual with Mac OSX 10.4.7. With no appliciations open, Kernel_task root is using 80% of both CPUs with 50 threads. If I restart the computer CPU usage for Kernel_Task drops to about 2% on both CPUs, but it will return to 80% (I think it comes back every time the computer awakes from sleep.) This only starting happing when I installed 10.4.7.

Any ideas??

kick52 · Jul 1, 2006, 05:08 PM

im using my PMG4 (sig) and kernal_task is only using 1%

ToneNN · Jul 3, 2006, 09:35 AM

Originally Posted by Phrogman

I've just noticed the same thing on my MDD 1ghz dual with Mac OSX 10.4.7. With no appliciations open, Kernel_task root is using 80% of both CPUs with 50 threads. If I restart the computer CPU usage for Kernel_Task drops to about 2% on both CPUs, but it will return to 80% (I think it comes back every time the computer awakes from sleep.) This only starting happing when I installed 10.4.7.

Any ideas??

Hey there,

I've noticed the same exact thing on my DA dual 533. I don't know for sure, but I also think it just started happening after the 10.4.7 update. Your observation about it coming back every time the computer awakes from sleep sounds right too - I hadn't had time to really look into it yet, but that was the impression I had as well.

At some point, I'll probably try seeing if I can install the 10.4.7 combo updater (rather than just the delta). But first, I wanted to look around the discussion boards a bit to see if anyone else was experiencing the same issue - it seems I'm not alone. I'l post back if I find out anything.

-Tone

Phrogman · Jul 3, 2006, 06:52 PM

There is a thread on this now on the Apple Support forums.

Linky

ToneNN · Jul 3, 2006, 07:15 PM

Originally Posted by Phrogman

There is a thread on this now on the Apple Support forums.

Linky

Here's my update: I tried running the combo updater as well as some permissions fixing and a battery of Open Firmware resets. None of these steps made a difference.

However, in my case, I've traced the issue to USB. I have an Adaptec USB2 PCI card installed. It's fine in and of itself, but I also have an external i-Rocks USB2 hub. If I use this hub in combination with the Adaptec card (plugged into it), the problem occurs when waking from sleep (or even when plugging the USB cable in after the computer wakes). Other devices plugged into the Adaptec card don't cause the issue, and if I plug the hub into a motherboard USB1 port, there is also no problem.

So it's only the combination of the two that causes it. And as others have said, the issue did not exist before 10.4.7.

Consule shows the following error when waking from sleep:

AppleUSBEHCI[0x243f800]::EnableAsyncSchedule: ERROR: USBCMD and USBSTS won't synchronize ON - cannot enable USB list processing

I'll be sure to post this on the Apple thread too. It seems unlikely that everyone having this problem has the exact hardware combination that I do (the card and hub) but there could be a variety of hardware compatibility issues at play causing the same kernal_task behavior with 10.4.7. Does anyone else with this problem have any PCI cards in their Macs?

-Tone

Phrogman · Jul 3, 2006, 07:20 PM

Interesting...I have a Compaq usb 2.0 card in mine with a belkin USB hub conected to it....I'll experiment with with out the card/hub and see what happens. I need this hub though, so it would suck to have to not use it.

Thanks

ToneNN · Jul 3, 2006, 07:25 PM

Originally Posted by Phrogman

Interesting...I have a Compaq usb 2.0 card in mine with a belkin USB hub conected to it....I'll experiment with with out the card/hub and see what happens. I need this hub though, so it would suck to have to not use it.

Thanks

And in the Apple thread, I noted that another individual with this problem has an Adaptec USB2 card listed in their signature.

*dramatic music!!!* dun-dun-dunnnn!

-Tone

Phrogman · Jul 3, 2006, 07:25 PM

Well, what do you know!! I unplugged the Belkin hub from the USB 2.0 card and my computer now wakes from sleep just fine. I plugged it back in and slept/woke the computer and the kernal_task was back of to 70% cpu usage.

Problem solved...sort of. I need this hub though.!!!!!!

ToneNN · Jul 3, 2006, 07:34 PM

Originally Posted by Phrogman

Well, what do you know!! I unplugged the Belkin hub from the USB 2.0 card and my computer now wakes from sleep just fine. I plugged it back in and slept/woke the computer and the kernal_task was back of to 70% cpu usage.

Problem solved...sort of. I need this hub though.!!!!!!

I'm glad to hear that you've now got a little more insight into the issue. I agree, though: losing the hub is not acceptable to me (I just bought mine a few months ago!). I just hope we don't have to wait until 10.4.8 for a solution.

-Tone

barney ntd · Jul 4, 2006, 06:02 AM

USB2 card/sleep problems are not new. I have an unbranded USB2 card plugged into my 400MHz sawtooth which works fine, provided I unplug every USB2 device before putting the computer to sleep. If I forget, the computer crashes when it tries to sleep. Plugging them back in after is no problem, so I just have a usb cable on my desk, and plug things in when I need them.

This problem has been the same since I got the card in Feb '05, back in the days of 10.3. No update has made any difference, and I don't expect a fix unless some Darwin hacker with the same problem decides to have a go at it.

Barney.

Phrogman · Jul 4, 2006, 01:35 PM

Originally Posted by barney ntd

USB2 card/sleep problems are not new. I have an unbranded USB2 card plugged into my 400MHz sawtooth which works fine, provided I unplug every USB2 device before putting the computer to sleep. If I forget, the computer crashes when it tries to sleep. Plugging them back in after is no problem, so I just have a usb cable on my desk, and plug things in when I need them.

This problem has been the same since I got the card in Feb '05, back in the days of 10.3. No update has made any difference, and I don't expect a fix unless some Darwin hacker with the same problem decides to have a go at it.

Barney.

May be....but my hub and card worked perfectly fine BEFORE the 10.4.7 update. Something changed in the update that screwed this up. I am hoping for a fix.

ToneNN · Jul 4, 2006, 06:53 PM

I think I came across a "solution" of sorts. Please note, however, that this is a hack. I'm not recommending anyone do this, but simply reporting that it worked for me.

The thread linked below (from the Apple boards) has a suggestion for working around other kinds of USB problems people have had with 10.4.7. I tried it, and it seems to have fixed my kernel_task issue as well. Basically, it involves restoring the 10.4.6 version of the IOUSBFamily.kext extension. It's possible this could cause other problems, but so far so good. Here's the details:

http://discussions.apple.com/thread....hreadID=542492

Do be sure to repair permissions after restoring the file. My Mac wouldn't boot correctly until I did so. So make sure you have an alternate boot volume, or an OS X Install disc just in case. It's also probably a good idea to make a backup of both the 10.4.6 and 10.4.7 IOUSBFamily.kext files, so you can switch between them as needed in the future.

Good luck!
-Tone

lundissimo · Jul 5, 2006, 04:26 PM

I re-installed a clean copy of OS X 10.3.9 on the G4 PowerMac with dual 450MHz cpus, keeping the old system in a "Previous Systems" folder, and keeping all user files. The cpu usage returned to its normal low level, no problem. As I re-installed the custom drivers for AudioPhile USB and Mouseworks, the Previous System folder was deleted, and everything is fine. I hate not finding out what the problem was, but results are what count.