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Subject: [hwloc-devel] hwloc is failing for Pentium D
From: Jirka Hladky (jhladky_at_[hidden])
Date: 2010-06-21 17:40:14

Hi guys,

I have been always impressed how well hwloc works. Now it seems like I have
found a bug on Pentium D, but it might be bug in linux kernel as well.

I have reproduced the bug on
Pentium D 820 (at Dell's PowerEdge SC430)
Pentium D 840 (at Dell's PowerEdge SC430)

It's dual core CPU with 2x1MB L2 cache. hwloc reports correct result only on
RHEL6.0 (public beta2) with kernel 2.6.32.

hwloc fails to report correct results on RHEL 5.5 (kernel 2.6.18) and RHEL 4.8
(kernel 2.6.9). Please see attached pdf files.

I have attached /proc/cpuinfo files as well. It might be a kernel bug as well

physical id : 0
siblings : 2
core id : 0
cpu cores : 2
apicid : 0
initial apicid : 0

is missing in /proc/cpuinfo on RHEL4.8 and RHEL5.5 for one the two CPUs.

I would welcome any feedback on this. Please let me know if you need more

Thanks a lot!