Usually misses 2nd processor

Is this a self-compiled kernel?

It's a standard feisty kernel, generic or low-latency.

The edgy kernels actually crashed unless it was a cold boot, hence my eary feisty switch

If you are 100% sure it is not an hardware failure than your best bet is to contact the kernel guru's directly (http://kernel.org).

Before you ask ... they do accept bug reports on non MM kernels.

Thanks for taking the time to report this bug and helping to make Ubuntu better. The output of 'sudo lspci -vv' and 'sudo lspci -vvn' may also be helpful. What type of hardware is this? Thanks in advance.

lspci -vv attached

lspci -vvn attached

thanks for looking at this

It booted with 2 cpu's, so have the same logs for comparison

lspci -vv

lspci -vvn
with 2 cpu active

The main observations are that when only 1 cpu is found it takes an extra 10 seconds to build the zonelists and it takes another 5 seconds for the other cpu to be declared not responding.

Beginning with the Hardy Heron 8.04 development cycle, all open Ubuntu kernel bugs need to be reported against the "linux" kernel package. We are automatically migrating this bug to the new "linux" package. However, development has already began for the upcoming Intrepid Ibex 8.10 release. It would be helpful if you could test the upcoming release and verify if this is still an issue - http://www.ubuntu.com/testing . If the issue still exists, please update this report by changing the Status of the "linux" task from "Incomplete" to "New". We appreciate your patience and understanding as we make this transition. Thanks!

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

I've moved to Interpid Ibex and I still have this problem even with
kernel 2.6.27-2-generic

Still often, only 1 cpu is recognized, although on Sunday 2 CPU were
recognized.

Sam

Still a problem with: 2.6.27-4-generic

Sample dmesg:
[ 0.004383] CPU: Physical Processor ID: 0
[ 0.004402] Checking 'hlt' instruction... OK.
[ 0.022333] ACPI: Core revision 20080609
[ 0.024434] ACPI: Checking initramfs for custom DSDT
[ 0.387239] ENABLING IO-APIC IRQs
[ 0.387426] ..TIMER: vector=0x31 apic1=0 pin1=2 apic2=-1 pin2=-1
[ 0.427304] CPU0: Intel(R) Pentium(R) 4 CPU 2.80GHz stepping 09
[ 0.428026] Booting processor 1/1 ip 6000
[ 5.529911] Not responding.
[ 5.529967] Inquiring remote APIC #1...
[ 5.529971] ... APIC #1 ID: failed
[ 5.530075] ... APIC #1 VERSION: failed
[ 5.530179] ... APIC #1 SPIV: failed
[ 5.530371] Brought up 1 CPUs
[ 5.530376] Total of 1 processors activated (5585.99 BogoMIPS).
[ 5.530401] CPU0 attaching sched-domain:
[ 5.530408] domain 0: span 0 level CPU
[ 5.530413] groups: 0
[ 5.530838] net_namespace: 840 bytes
[ 5.530851] Booting paravirtualized kernel on bare hardware

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to https://wiki.ubuntu.com/KernelTeamBugPolicies for more information. Thanks.

I'm still getting the bug in 2.6.27-11, though at the moment all four of my cores have been recognized.

Attaching what it should look like.

My problem has returned, and thus far I have been unsuccessful in returning to the desired functionality.

I've given jaunty a few goes now and I often miss the second core still.

Sam

This may be a fluke, but I was trying to see if this would work, and it did: I booted into Windows, to verify that it saw all four of my cores. It did (Task Manager/Performance showed four graphs for CPU usage), and when I rebooted into Intrepid, all four cores were recognized by the kernel. I also noticed that the kernel didn't pause on APIC loading this time, either (I have taken out the "quiet" kernel parameter, so I have better insight as to what's going on with the booting kernel).

Just FYI. I will hold off on Jaunty until it's fully released, then I intend to reinstall this machine with an x86_64 system, to see if that makes a difference.

I observed the same kind of defect on an AMD Phenom 9550 Quad Core: most of the time only one CPU is recognized and the others are indicated as "not responding", and sometimes all four are present. Disabling or enabling ACPI does not change anything, the cores are not more often recognized.

One thing that changed the deal was to switch off the Ubuntu splash boot and disable any kind of VGA=xxx line in the kernel arguments. For some reason the boot process is much faster that way and has always caught all four CPUs so far, but that probably needs more experimentation.

N.

Finally got it to work by trial and error. If I boot the machine with 'noapic' and remove all splash and vga= options I systematically get all cores recognized. Seems like 'noapic' is the real key here. Without it, booting can bring up 1, 2 or 4 cores in a seemingly random fashion.

> Finally got it to work by trial and error. If I boot the machine with 'noapic' and remove all splash and
> vga= options I systematically get all cores recognized. Seems like 'noapic' is the real key here.
> Without it, booting can bring up 1, 2 or 4 cores in a seemingly random fashion.

See, that's weird, because it used to be that disabling APIC would disable SMP. Maybe it doesn't work that way anymore, I'll try to give it a shot. Thanks for the workaround!

OK, after setting the kernel line with "noapic" and removing "splash", it boots with all cores. I haven't done more than this boot, although... the real first boot gave me some dreaded "not responding" messages, then it hung on initializing APIC.

I don't understand why the splash screen makes a difference here, but again I'm not a developer nor a PC architecture geek.

Well, I thought it was fixed, but I had to reboot due to a power outage, and now I only have one core active (as seen through /proc/cpuinfo).

I haven't upgraded to Jaunty yet, I was planning on doing a reinstall with x86_64, to see if that makes a difference. I'll let you know what results I get.

This bug report was marked as Triaged a while ago but has not had any updated comments for quite some time. Please let us know if this issue remains in the current Ubuntu release, http://www.ubuntu.com/getubuntu/download . If the issue remains, click on the current status under the Status column and change the status back to "New". Thanks.

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This problem still exists, in both Jaunty and Karmic. See my extensive troubleshooting in Karmic here:

https://bugs.launchpad.net/ubuntu/+source/linux/+bug/515270

I've moved this machine to another purpose, it now runs Windows 7. I'm too much of a Linux geek and I haven't figured out how to verify the Win7 machine is loaded with four cores, so I haven't ruled out the possibility of a hardware problem. In my previous testing, Windows XP showed four cores (before I reimaged it).

Still a problem for me.

This bug report was marked as Incomplete and has not had any updated comments for quite some time. As a result this bug is being closed. Please reopen if this is still an issue in the current Ubuntu release http://www.ubuntu.com/getubuntu/download . Also, please be sure to provide any requested information that may have been missing. To reopen the bug, click on the current status under the Status column and change the status back to "New". Thanks.

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Jeremy, you marked this as incomplete on 2010-03-13 but you didn't say what information you still wanted.

10 hours ago, you said (in an automated fashion) "and has not had any updated comments for quite some time" but comments were made by Jeremy with notes to extensive trouble shooting on the same day you marked it as incomplete.

I commented a month later to say I still had the trouble too.

Please justify the change from triaged to incomplete and say what information you still need.

I will run "apport-collect -p linux 97554" this week with a fresh install

@Sam -- it doesn't look like you ever got to this apport-collect? Is this issue still present? Please do confirm that and get the apport information you indicated above.

10.10 live CD detects both processors, so I think you can close this one

Do you still want the apport? If so can you have it from the live cd or do you want an installation?

This bug report was marked as Incomplete and has not had any updated comments for quite some time. As a result this bug is being closed. Please reopen if this is still an issue in the current Ubuntu development release http://cdimage.ubuntu.com/daily-live/current/ . Also, please be sure to provide any requested information that may have been missing. To reopen the bug, click on the current status under the Status column and change the status back to "New". Thanks.

[This is an automated message. Apologies if it has reached you inappropriately; please just reply to this message indicating so.]