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How to verify SMP Working on Ubuntu

Asked by ted.bellinger@terpalum.umd.edu

I am running 2.6.22-14-386 on a dual P-III (866 mhz), which seems to run very slowly. Granted, I am handicapped by having only 192 MB RAM and a small HD (~4 GB), but I would have thought the machine would perform better under Ubuntu than under Win95. Note, /proc/cpuinfo is empty, although both CPUs show in BIOS.

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Albert Damen
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Robert Di Gioia (digioiar) said : 		#1

Hi!

Don't know why /proc/cpuinfo is empty, but you should be able to see if the kernel is using SMP code by issuing the following command.

grep -i smp /var/log/syslog

If you see a line similar to below, then SMP is enabled.

SMP alternatives: switching to SMP code

You can also grep for cpu and see if the system is recognizing both CPUs.

Hope this helps.

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ted.bellinger@terpalum.umd.edu (ted-bellinger) said : 		#2

Here's what I got:

ted@ted-desktop:~$ grep -i smp /var/log/syslog
Dec 27 12:43:19 ted-desktop kernel: [ 0.000000] found SMP MP-table at 000fe710
Dec 27 12:43:19 ted-desktop kernel: [ 0.000000] Using ACPI (MADT) for SMP configuration information
ted@ted-desktop:~$ grep -i cpu /var/log/syslog
Dec 27 12:43:19 ted-desktop kernel: [ 0.000000] WARNING: NR_CPUS limit of 1 reached. Processor ignored.
Dec 27 12:43:19 ted-desktop kernel: [ 0.000000] Initializing CPU#0
Dec 27 12:43:19 ted-desktop kernel: [ 229.427126] SLUB: Genslabs=22, HWalign=32, Order=0-1, MinObjects=4, CPUs=1, Nodes=1
Dec 27 12:43:19 ted-desktop kernel: [ 229.507417] CPU: After generic identify, caps: 0383fbff 00000000 00000000 00000000 00000000 00000000 00000000
Dec 27 12:43:19 ted-desktop kernel: [ 229.507442] CPU: L1 I cache: 16K, L1 D cache: 16K
Dec 27 12:43:19 ted-desktop kernel: [ 229.507448] CPU: L2 cache: 256K
Dec 27 12:43:19 ted-desktop kernel: [ 229.507455] CPU: After all inits, caps: 0383fbff 00000000 00000000 00000040 00000000 00000000 00000000
Dec 27 12:43:19 ted-desktop kernel: [ 229.507501] CPU: Intel Pentium III (Coppermine) stepping 03
Dec 27 12:43:19 ted-desktop kernel: [ 230.571008] checking if image is initramfs...<6>Switched to high resolution mode on CPU 0
Dec 27 12:43:21 ted-desktop NetworkManager: <debug> [1198777401.293645] nm_hal_device_added(): New device added (hal udi is '/org/freedesktop/Hal/devices/acpi_CPU0').
ted@ted-desktop:~$
ted@ted-desktop:~$ grep -i smp /var/log/syslog
Dec 27 12:43:19 ted-desktop kernel: [ 0.000000] found SMP MP-table at 000fe710
Dec 27 12:43:19 ted-desktop kernel: [ 0.000000] Using ACPI (MADT) for SMP configuration information

What might cause the fol error/warning:
WARNING: NR_CPUS limit of 1 reached. Processor ignored"
Does my kernel not support SMP?

Ted

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Albert Damen (albrt) said : 		#3

Indeed, the i386 kernels like 2.6.22-14-386 do not support SMP. For SMP you will need to use the 2.6.22-14-generic kernel.

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ted.bellinger@terpalum.umd.edu (ted-bellinger) said : 		#4

I must not understand something. When I go to Synaptic and search on generic, It shows that linux-generic (2.6.22.14.21) is installed as well as linux-image-2.6.22-14-386. Do I need to do something to get it to use the generic kernel?

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Best Albert Damen (albrt) said : 		#5

If the generic kernel is properly installed, you should have an option to use that kernel when you boot.
When you boot, you will either get the boot menu directly or you get a message counting down and saying to press enter to enter the boot menu. Once you see the boot menu it should have a line with the -generic kernel. If you select that line, you will boot into the generic kernel. Then you can do the test mentioned by Robert again.

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ted.bellinger@terpalum.umd.edu (ted-bellinger) said : 		#6

Thanks albert, that solved my question.