Hello,
I've recently been told that the siblings field in /proc/cpuinfo should
have a count of 2 when hyperthreading is enabled in the bios of a
machine and should drop to 1 when hyperthreading is disabled in the bios
of a machine. I have a vendor who is using this algorithm to decide
whether they should divide by 2 on the number of processors showing in
/proc/cpuinfo to obtain the real count of physical processors in the
machine. I've noticed on my Dell 2-cpu Xeon, that siblings field does
not change when you enable/disable the hyperthreading feature in the
bios (only the number of processors seen in /proc/cpuinfo). My question
I guess is this a bug in the bios of my Dell box(should siblings count
drop to 1 when hyperthreading is disabled?). I would think a better
approach for the vendor would be to look at the physical ID field in
/proc/cpuinfo since I've noticed that each real physical cpu has a
different ID.
Please CC me on answers since I'm not on the list. Thanks for any
insight you provide.
Rich Wohlstadter
Genome Sequencing Center
Washington University of Saint Louis
[email protected]