Bug 217134

Are the processors in this machine multi-core? On perfmon2 there were some
problems with the cpu id code that appeared to identify multicore P4 processors
as hyperthreaded processors.

Could the /proc/cpuinfo for both HT and HT disabled be included in the bug
report to see whether this is similar problem?

No, simple P4 HT, no multicore.

Without HT (disabled in BIOS):

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      :               Intel(R) Pentium(R) 4 CPU 3.60GHz
stepping        : 1
cpu MHz         : 3591.169
cache size      : 1024 KB
physical id     : 0
siblings        : 1
core id         : 0
cpu cores       : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 3
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 syscall nx lm constant_tsc
up pni monitor ds_cpl tm2 cid cx16 xtpr
bogomips        : 7187.51
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:


With HT enabled:

processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      :               Intel(R) Pentium(R) 4 CPU 3.60GHz
stepping        : 1
cpu MHz         : 3591.167
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 3
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 syscall nx lm constant_tsc
pni monitor ds_cpl tm2 cid cx16 xtpr
bogomips        : 7187.52
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      :               Intel(R) Pentium(R) 4 CPU 3.60GHz
stepping        : 1
cpu MHz         : 3591.167
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 3
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 syscall nx lm constant_tsc
pni monitor ds_cpl tm2 cid cx16 xtpr
bogomips        : 7182.05
clflush size    : 64
cache_alignment : 128
address sizes   : 36 bits physical, 48 bits virtual
power management:

I can replicate this problem on RHEL-4U4 system:

2.6.9-42.0.3.ELsmp #1 SMP Mon Sep 25 17:24:31 EDT 2006 x86_64 x86_64 x86_64
GNU/Linux

The oprofile kernel module is mis identifying the whether the ht is on or off.

Created attachment 144140 [details]
Determine number of logical processors active

The attached patch was discussed on the oprofile mailing list. Not sure that
this will deal properly with the case of multiple cores in a package.

Created attachment 226031 [details]
Check the number of processors that are actually active

I check out the current 2.6.23 kernel via git and was able to replicate the
problem on a xeon (net burst based machine) running the upstream kernel. The
attached patch allowed the oprofile module to correctly identify the processor
and non-hyperthreaded when it was diabled in the bios.

The question is are there any intel processors that have more than one net
burst core in the same socket? If so, this patch may still fail. If Intel
doesn't have any multicore netburst processors, this change should be
sufficient.

Fedora apologizes that these issues have not been resolved yet. We're
sorry it's taken so long for your bug to be properly triaged and acted
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This bug is open for a Fedora version that is no longer maintained and
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