Linpack Benchmark Only Running On 2 of 4 cores

[elliotc]

Sorry if this is rather is rather trivial but I'm having some difficulties getting the benchmark to run across all four cores of a twin socket dual-core machine.

I am attempting to benchmark a Dell Poweredge SC1425 it has a couple of dual core Xeons (I have posted the output from /proc/cpuinfo at the bottom) and am running the file:

/linpack_10.2.0/benchmarks/linpack/lininput_xeon32

The file is as it came, i.e. unedited (yes, you are dealing with someone that ignorant). Top is showing:

top - 14:44:10 up 23:56, 3 users, load average: 1.41, 0.99, 1.06
Tasks: 79 total, 3 running, 76 sleeping, 0 stopped, 0 zombie
Cpu0 :100.0%us, 0.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu1 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu2 :100.0%us, 0.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu3 : 0.3%us, 0.3%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 2076120k total, 1903244k used, 172876k free, 23536k buffers
Swap: 4008120k total, 0k used, 4008120k free, 87384k cached

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
16148 root 20 0 1727m 1.7g 656 R 100 84.9 0:50.63 xlinpack_xeon32
16220 root 20 0 1727m 1.7g 656 R 100 84.9 0:27.24 xlinpack_xeon32


and ps:

root 3086 0.0 0.1 8160 2708 ? Ss 13:32 0:02 \_ sshd: root@pts/0
root 3094 0.0 0.1 5132 2688 pts/0 Ss 13:32 0:01 | \_ -bash
root 14143 0.1 0.0 3848 1172 pts/0 S+ 14:32 0:00 | \_ /bin/bash ./runme_xeon32
root 14146 99.8 84.9 1769204 1763468 pts/0 R+ 14:32 1:28 | \_ ./xlinpack_xeon32 lininput_xeon32
root 14217 0.0 84.9 1769204 1763468 pts/0 S+ 14:32 0:00 | \_ ./xlinpack_xeon32 lininput_xeon32
root 14218 0.0 84.9 1769204 1763468 pts/0 S+ 14:32 0:00 | \_ ./xlinpack_xeon32 lininput_xeon32
root 14219 100 84.9 1769204 1763468 pts/0 R+ 14:32 1:05 | \_ ./xlinpack_xeon32 lininput_xeon32

However, the top of the output file reads:

Wed Aug 12 14:32:24 UTC 2009
Intel LINPACK data

Current date/time: Wed Aug 12 14:32:24 2009

CPU frequency: 2.800 GHz
Number of CPUs: 4
Number of threads: 4

Which looks like it got the number or cores correct but as far as I can tell it is only executing on two of them in two threads. I have tried setting the OMP_NUM_THREADS to 4 with no effect.

I would really apprecaite any help you could provide. And apologies in advance if I've been really dense.

Thanks
Elliot

CPU info follows:

processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel Xeon CPU 2.80GHz
stepping : 3
cpu MHz : 2800.328
cache size : 2048 KB
physical id : 0
siblings : 2
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 dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pebs bts pni monitor ds_cpl cid cx16 xtpr
bogomips : 5605.43
clflush size : 64
power management:

processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel Xeon CPU 2.80GHz
stepping : 3
cpu MHz : 2800.328
cache size : 2048 KB
physical id : 3
siblings : 2
core id : 0
cpu cores : 1
apicid : 6
initial apicid : 6
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 dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pebs bts pni monitor ds_cpl cid cx16 xtpr
bogomips : 5600.29
clflush size : 64
power management:

processor : 2
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel Xeon CPU 2.80GHz
stepping : 3
cpu MHz : 2800.328
cache size : 2048 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
apicid : 1
initial apicid : 1
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 dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pebs bts pni monitor ds_cpl cid cx16 xtpr
bogomips : 5600.24
clflush size : 64
power management:

processor : 3
vendor_id : GenuineIntel
cpu family : 15
model : 4
model name : Intel Xeon CPU 2.80GHz
stepping : 3
cpu MHz : 2800.328
cache size : 2048 KB
physical id : 3
siblings : 2
core id : 0
cpu cores : 1
apicid : 7
initial apicid : 7
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 dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pebs bts pni monitor ds_cpl cid cx16 xtpr
bogomips : 5600.25
clflush size : 64
power management:

[Ying_H_Intel]

It may be a same issue discribledas Intel MKL threading behavior on Hyper-Threading systems.

Regards,
Ying