Uncertain if quad-core processor recognised

[walawa]

Hi,
I've been using Ubuntu on with an Intel Quad-Core Q6600, but I am currently starting to doubt if all four cores are recognized. I noticed this when I launched Conky and it said that I was trying to monitor more cores than I had. I then went to system monitor and I realized it only shows one core. I checked the BIOS and all four cores are shown and enabled.

I ran "cat /proc/cpuinfo" : processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
stepping : 11
cpu MHz : 2399.950
cache size : 4096 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc up arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4799.90
clflush size : 64
power management:

I'm not fully sure how to interpret this, but 1 is under cpu cores.

I'm not certain, but I think this may have something to do with updating from 8.04 to 8.10. After the upgrade I noticed the system was slower than before and now I've just noticed what I mentioned above. Another possibility would be that I recently installed Windows on a separate partition. Windows is also pretty slow, but it isn't necessary to me so I don't really mind. Could any of these things be what's causing my problem?

Is there a way to check if Ubuntu recognizes my processor, and if not how can I fix this?

[blueridgedog]

What is the output of

sudo lshw -class cpu

[walawa]

Here's th ouput: *-cpu
description: CPU
product: Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
vendor: Intel Corp.
physical id: 4
bus info: cpu@0
version: 6.15.11
serial: 0000-06FB-0000-0000-0000-0000
slot: Socket 775
size: 600MHz
width: 64 bits
clock: 66MHz
capabilities: fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx x86-64 constant_tsc up arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
configuration: id=0
*-logicalcpu:0
description: Logical CPU
physical id: 0.1
width: 64 bits
capabilities: logical
*-logicalcpu:1
description: Logical CPU
physical id: 0.2
width: 64 bits
capabilities: logical
*-logicalcpu:2
description: Logical CPU
physical id: 0.3
width: 64 bits
capabilities: logical
*-logicalcpu:3
description: Logical CPU
physical id: 0.4
width: 64 bits
capabilities: logical

[blueridgedog]

Well, it sees them there...

You can install sysstat with:

sudo apt-get install systat

Then run:

mpstat -P ALL

Which should give you a list of the load of each core.

[igknighted]

Each "core" is listed as a separate processor. So each core only has one core, but there should be four CPUs (CPU0-CPU3)

[bettlebrox]

"cat /proc/cpu" should list all of your cores. If if it only shows one core then your kernel is only using one core.

Which kernel & version are you using? The output of "uname -a" will display that info.

Any recent kernels that Ubuntu should be multi-core/smp aware, so it's possible this is a misconfiguration somewhere.

[walawa]

mpstat -P ALL:
Linux 2.6.27-9-generic (tristan-desktop) 07/02/09 _i686_

01:07:05 PM CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s
01:07:05 PM all 19.38 0.11 3.88 1.59 0.31 0.18 0.00 74.55 509.53
01:07:05 PM 0 19.38 0.11 3.88 1.59 0.31 0.18 0.00 74.55 332.08

uname -a:
Linux tristan-desktop 2.6.27-9-generic #1 SMP Thu Nov 20 21:57:00 UTC 2008 i686 GNU/Linux

The output of "cat /proc/cpu" is "no such file or directory". Why is this?

[blueridgedog]

Odd...mpstat is only showing one cpu. Perhaps another forum member can post a better tool.

[anders_c_]

its supposed to be:
cat /proc/cpuinfo

[walawa]

cat /proc/cpuinfo: processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Quad CPU Q6600 @ 2.40GHz
stepping : 11
cpu MHz : 2399.950
cache size : 4096 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc up arch_perfmon pebs bts pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4799.90
clflush size : 64
power management:

[blueridgedog]

Just a wild idea, but you might try booting into an older kernel (if you system is a few months old, you should have several kernel options when you boot) and run the mpstat command under a different kernel version.

[anders_c_]

there should be one folder for each core in:
/sys/devices/system/cpu

i have 2 cores so i have the folders:
/sys/devices/system/cpu/cpu0
/sys/devices/system/cpu/cpu1

all cores except "cpu0" should have a file called online in them
if that file contains a zero the core will be offline, so try:
cat /sys/devices/system/cpu/cpu1/online
cat /sys/devices/system/cpu/cpu2/online
cat /sys/devices/system/cpu/cpu3/online

if it says "0" change them to "1" by opening a root terminal and typing:
echo "1" > /sys/devices/system/cpu/cpu1/online

IT HAS TO BE A ROOT TERMINAL, sudo wont work...not really sure why but it
has something to do with the ">"

if this doesnt work or if u dont even have one folder for each core in
/sys/devices/system/cpu/ then i have no clue, perhaps a reinstall??

[bettlebrox]

Your kernel version looks fine:
2.6.27-9-generic #1 SMP

It's possible to disable SMP (and hence multi-core support) at boot time. Did you make any changes to your grub configuration?

Also, start up top from the a shell (command-line). By default it doesn't show all the cores, but if you press "1" it'll show all the CPU/Core's and load on each one. Try and see if you see more than one Core.

[ectospasm]

there should be one folder for each core in:
/sys/devices/system/cpu

i have 2 cores so i have the folders:
/sys/devices/system/cpu/cpu0
/sys/devices/system/cpu/cpu1

all cores except "cpu0" should have a file called online in them
if that file contains a zero the core will be offline, so try:
cat /sys/devices/system/cpu/cpu1/online
cat /sys/devices/system/cpu/cpu2/online
cat /sys/devices/system/cpu/cpu3/online

if it says "0" change them to "1" by opening a root terminal and typing:
echo "1" > /sys/devices/system/cpu/cpu1/online

IT HAS TO BE A ROOT TERMINAL, sudo wont work...not really sure why but it
has something to do with the ">"

if this doesnt work or if u dont even have one folder for each core in
/sys/devices/system/cpu/ then i have no clue, perhaps a reinstall??

I've only got one cpuN device in /sys/devices/cpu/. A reinstall is pathetic at this point, since I KNOW it was working with this very kernel previously. I tried downgrading to the 2.6.27-9 kernel, to no avail.

Here's output of various commands. lshw apparently shows that I should be seeing all four cores, but the kernel et al. show nothing:

amphetamine:~ # cat /proc/cpuinfo
processor : 0
vendor_id : AuthenticAMD
cpu family : 16
model : 2
model name : AMD Phenom(tm) 9950 Quad-Core Processor
stepping : 3
cpu MHz : 2600.000
cache size : 512 KB
physical id : 0
siblings : 1
core id : 0
cpu cores : 1
apicid : 0
initial apicid : 0
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs
bogomips : 5199.85
clflush size : 64
power management: ts ttp tm stc 100mhzsteps hwpstate

amphetamine:~ # lshw -class cpu
*-cpu:0
description: CPU
product: AMD Phenom(tm) 9950 Quad-Core Processor
vendor: Advanced Micro Devices [AMD]
physical id: 3
bus info: cpu@0
version: 15.2.3
slot: Socket AM2
size: 2600MHz
capacity: 2600MHz
width: 64 bits
clock: 200MHz
capabilities: boot fpu fpu_exception wp vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp x86-64 3dnowext 3dnow constant_tsc pni monitor cx16 popcnt lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs cpufreq
*-cpu:1
physical id: 4
bus info: cpu@1
version: 15.2.3
size: 18EHz
*-cpu:2
physical id: 5
bus info: cpu@2
version: 15.2.3
size: 18EHz
*-cpu:3
physical id: c
bus info: cpu@3
version: 15.2.3
size: 18EHz
*-processor UNCLAIMED
description: Co-processor
product: MCP78S [GeForce 8200] Co-Processor
vendor: nVidia Corporation
physical id: 1.3
bus info: pci@0000:00:01.3
version: a2
width: 32 bits
clock: 66MHz
capabilities: bus_master
configuration: latency=0 maxlatency=1 mingnt=3


I KNOW it was working before, and the only thing I really changed was a routine kernel upgrade. I'm wondering if this is a bug? Or a failing chip? I dunno...

[walawa]

I only have a folder named cpu0 and another named cpuidle in /sys/devices/system/cpu. I have made changes to grub. I recently installed Windows over Ubuntu and had to make some changes for it to work.

Also, start up top from the a shell (command-line). By default it doesn't show all the cores, but if you press "1" it'll show all the CPU/Core's and load on each one. Try and see if you see more than one Core.
I'm not sure how to start up form the shell. Do you mean login without X?

[unutbu]

On a dual core processor, this is the output of "dmesg | grep -i cpu":

% dmesg | grep -i cpu
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] ACPI: SSDT 3FEE7CA0, 0380 (r1 PmRef CpuPm 3000 INTL 20040311)
[ 0.000000] SMP: Allowing 4 CPUs, 2 hotplug CPUs
[ 0.000000] PERCPU: Allocating 41628 bytes of per cpu data
[ 0.000000] NR_CPUS: 64, nr_cpu_ids: 4, nr_node_ids 1
[ 0.000000] Initializing CPU#0
[ 0.004000] SLUB: Genslabs=12, HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.004000] Initializing cgroup subsys cpuacct
[ 0.004000] CPU: L1 I cache: 32K, L1 D cache: 32K
[ 0.004000] CPU: L2 cache: 1024K
[ 0.004000] CPU: Physical Processor ID: 0
[ 0.004000] CPU: Processor Core ID: 0
[ 0.433808] CPU0: Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz stepping 0d
[ 0.004000] Initializing CPU#1
[ 0.004000] CPU: L1 I cache: 32K, L1 D cache: 32K
[ 0.004000] CPU: L2 cache: 1024K
[ 0.004000] CPU: Physical Processor ID: 0
[ 0.004000] CPU: Processor Core ID: 1
[ 0.520411] CPU1: Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz stepping 0d
[ 0.520428] checking TSC synchronization [CPU#0 -> CPU#1]: passed.
[ 0.524055] Brought up 2 CPUs
[ 0.524080] CPU0 attaching sched-domain:
[ 0.524093] CPU1 attaching sched-domain:
[ 0.576042] Switched to high resolution mode on CPU 0
[ 0.576457] Switched to high resolution mode on CPU 1
[ 2.148572] cpuidle: using governor ladder
[ 2.148575] cpuidle: using governor menu
[ 2.275330] ACPI: SSDT 3FEE7680, 022A (r1 PmRef Cpu0Ist 3000 INTL 20040311)
[ 2.275856] ACPI: SSDT 3FEE7B40, 0152 (r1 PmRef Cpu1Ist 3000 INTL 20040311)
[ 3.417141] [<c010288d>] cpu_idle+0x7d/0x140

Notice the line that says "Brought up 2 CPUs".
Sometimes dmesg contains useful error messages.
Perhaps take a look at and post your "dmesg | grep -i cpu"

Also, post

uname -a

This will tell us which kernel you are using.

[ectospasm]

On a dual core processor, this is the output of "dmesg | grep -i cpu":...


Yeah, the boot messages say only one CPU has been started. Unfortunately I have no idea why, since it stopped working afaict on its own. Reverting back to a previous kernel doesn't fix it, so I doubt the problem lies in the options compiled into (or left out of) my running kernel.

amphetamine:~ # dmesg | grep -i cpu
[ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] SMP: Allowing 4 CPUs, 0 hotplug CPUs
[ 0.000000] PERCPU: Allocating 41628 bytes of per cpu data
[ 0.000000] NR_CPUS: 64, nr_cpu_ids: 4, nr_node_ids 1
[ 0.000000] Kernel command line: root=UUID=5b026cc0-09be-4255-8023-54c95619ca42 ro cpus=4 splash
[ 0.000000] Initializing CPU#0
[ 0.004000] SLUB: Genslabs=12, HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[ 0.004000] Initializing cgroup subsys cpuacct
[ 0.004000] CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)
[ 0.004000] CPU: L2 Cache: 512K (64 bytes/line)
[ 0.004000] CPU 0(4) -> Core 0
[ 0.333158] CPU0: AMD Phenom(tm) 9950 Quad-Core Processor stepping 03
[ 16.512119] Brought up 1 CPUs
[ 16.512284] CPU0 attaching NULL sched-domain.
[ 16.900044] Switched to high resolution mode on CPU 0
[ 17.970274] cpuidle: using governor ladder
[ 17.970336] cpuidle: using governor menu
[ 51.589855] powernow-k8: Found 1 AMD Phenom(tm) 9950 Quad-Core Processor processors (1 cpu cores) (version 2.20.00)
amphetamine:~ # uname -a
Linux amphetamine 2.6.27-11-generic #1 SMP Thu Jan 29 19:24:39 UTC 2009 i686 GNU/Linux


It seems that WinXP can see all four cores, unless my CPU has failed and Windows just sucks.

[walawa]

Here's the output of dmesg | grep -i cpu: [ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] SMP: Allowing 1 CPUs, 0 hotplug CPUs
[ 0.000000] PERCPU: Allocating 41628 bytes of per cpu data
[ 0.000000] NR_CPUS: 64, nr_cpu_ids: 1, nr_node_ids 1
[ 0.000000] Initializing CPU#0
[ 0.004000] SLUB: Genslabs=12, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.004192] Initializing cgroup subsys cpuacct
[ 0.004206] CPU: L1 I cache: 32K, L1 D cache: 32K
[ 0.004208] CPU: L2 cache: 4096K
[ 0.004210] CPU: Physical Processor ID: 0
[ 0.004211] CPU: Processor Core ID: 0
[ 0.300052] weird, boot CPU (#0) not listedby the BIOS.
[ 0.304019] Brought up 1 CPUs
[ 0.304019] CPU0 attaching sched-domain:
[ 0.304019] domain 0: span 0 level CPU
[ 0.928064] Switched to high resolution mode on CPU 0
[ 1.396353] cpuidle: using governor ladder
[ 1.396355] cpuidle: using governor menu
[ 1.884046] ACPI: Processor [CPU0] (supports 8 throttling states)
Mine also says only one cpu has been started out of the four.

My kernel is Linux tristan-desktop 2.6.27-9-generic #1 SMP Thu Nov 20 21:57:00 UTC 2008 i686 GNU/Linux.

I don't know if this has anything to do with it, but I'm using Phoenix BIOS.

[walawa]

I tried booting from an 8.04 LiveCD but system monitor still didn't recognize all 4 cores. Could booting into a more recent LiveCD help?

I've seen posts where booting with acpi off helped. Should I try this?

Would using 64-bit ubuntu help?

[unutbu]

Try booting with kernel option "noapic".

This is where I'm getting this information:
http://fixunix.com/linux/269544-weird-boot-cpu-0-not-listed-bios.html

If that does not work, try "acpi=off".

And here are instructions for booting with kernel options:
http://ubuntuforums.org/showpost.php?p=5586563&postcount=4

[blueridgedog]

My concern is this is not something that is particular to the systems listed, but may be more general for specific CPUs or kernel versions. Perhaps some other members will chime in with reports of support for their quad core CPUs.

[bapoumba]

Moved to hardware (thanks blueridgedog ;))

[walawa]

I tried booting with noapic and then with acpi=off at the end of the kernel line, but it did not make a difference.

This is the output of dmesg | grep -i cpu: [ 0.000000] Initializing cgroup subsys cpuset
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] SMP: Allowing 1 CPUs, 0 hotplug CPUs
[ 0.000000] PERCPU: Allocating 41628 bytes of per cpu data
[ 0.000000] NR_CPUS: 64, nr_cpu_ids: 1, nr_node_ids 1
[ 0.000000] Initializing CPU#0
[ 0.004000] SLUB: Genslabs=12, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
[ 0.004189] Initializing cgroup subsys cpuacct
[ 0.004202] CPU: L1 I cache: 32K, L1 D cache: 32K
[ 0.004205] CPU: L2 cache: 4096K
[ 0.004207] CPU: Physical Processor ID: 0
[ 0.004208] CPU: Processor Core ID: 0
[ 0.024039] weird, boot CPU (#0) not listedby the BIOS.
[ 0.132067] Brought up 1 CPUs
[ 0.132078] CPU0 attaching sched-domain:
[ 0.132080] domain 0: span 0 level CPU
[ 1.116669] cpuidle: using governor ladder
[ 1.116671] cpuidle: using governor menu

Could the line that says "SMP: Allowing 1 CPUs, 0 hotplug CPUs" have anything to do with the problem?

[blueridgedog]

Perhaps it is certain Bios(es) and certain CPU's that the kernal has trouble with?

[unutbu]

I agree with blueridgedog. Please run

sudo lshw | bzip2 -c > lshw.bz2 and attach lshw.bz2 to a post so we'll know the make/model of your machine, motherboard, bios, and cpus.

Googling any of those keywords along with "SMP Allowing 1 CPUs" or "weird, boot CPU (#0) not listedby the BIOS" might also be useful.

[ectospasm]

Perhaps it is certain Bios(es) and certain CPU's that the kernal has trouble with?

In that case I'd expect it to be consistent, that it would either recognize or fail to recognize all four of my cores 100% of the time. For me at least, I'm guessing that it fails to recognize all four cores about 85% of the time. Right now, I'm in a boot that sees all four cores. If I reboot, I suspect only one core will come up.

[anv]

Sorry to disturb, but I noticed exactly same behavior on my AMD quad-core processor this was my original question:

http://ubuntuforums.org/showthread.php?t=1060923

but as I did some of those first steps in this section, I noticed also that it gives just one cpu. but one thing also as I noticed while doing renderings and following the system from Htop if I stopped and continued it took core 3 instead of the core 4

[unutbu]

For what it's worth, here is a testimonial that the Core 2 Quad Q6600 processor is compatible with Ubuntu 8.10 (both 32- and 64-bit):
https://lists.ubuntu.com/archives/ubuntu-users/2009-January/170329.html

[blueridgedog]

One has to wonder if the author of that post actually verified that all four cores were running rather than the system working. I am ordering a quad core this week, so soon I will have another statistic to add to the issue.

[walawa]

The output of "sudo lshw | bzip2 -c > lshw.bz2" is attached to this post.

Does ubuntu 8.10 use the 386 or 686 kernel? I've read that 686 is better for Intel processors. Is this true?

[walawa]

Would a fresh install fix the problem? Could installing 64 bit ubuntu or booting into a LiveCD help?

Perhaps it is certain Bios(es) and certain CPU's that the kernal has trouble with?
Is there a way to reinstall the kernel, or something along those lines?

[blueridgedog]

Well, you might try booting off of the 32 bit and 64 bit live cd and seeing if it sees all four cores.

[walawa]

I'll probably try booting into a 64-bit LiveCD later today. Would compiling a new kernel possibly fix this issue?

[blueridgedog]

I don't think so, but I would verify the kernels you have tried and then submit a bug report:

https://launchpad.net/ubuntu/+filebug

I feel strongly that it is a combination of certain chipsets/bioses/cpus.

[walawa]

It's fixed. System monitor now shows all four cores. The problem was that apic wasn't disabled in the kernel line, but it was in the BIOS setup. I'd already checked the BIOS to make sure all cores were enabled, but I guess I didn't notice the apic option.

Thanks for your help.

[unutbu]

Congratulations, walawa, and thank you for posting your solution!
What did you do differently between now and post #23 (http://ubuntuforums.org/showpost.php?p=6700480&postcount=23) when you tried booting with "noapic" ?

[walawa]

In post #23 I was trying to boot with acpi disabled because I'd read it could help, but this did not make a difference because I didn't know that acpi was already disabled in the BIOS. The problem was that I've been booting with acpi disabled without knowing it. So I enabled it and now everything works fine.

[bettlebrox]

Great! Glad you got the 4 cores enabled. :)

[ectospasm]

It seems to be hit or miss with me. Earlier this month I posted on launchpad, I'm not sure why I didn't post here. My original bug post was marked as a duplicate of this: Bug#97554 (https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.20/+bug/97554)

And no, disabling APIC is not a viable solution. The way I understand it, that would disable SMP altogether, which is not what I want.