Boot to RHEL6.0 fail with BDW CPU

Hi All,

This is my first post here, please let me know if anything wrong.

We found that if we populated 2 BDW B0 CPU (22 Core with EIST enabled=88 threads), system hang when booting RHEL6.

If we populated 2*BDW A1 CPU (16 core with EIST enabled = 64 threads), system can boot to RHEL6 successfully.

We guess it is a thread limitation in RHEL 6, so we removed 1 BDW B0 CPU from system and keep EIST enabled (44 threads), However, this configuration still failed to boot RHEL6.0

We try to reduce process core and found that if we set 16 core and set EIST enabled on BDW B0 CPU, system can boot to RHEL6.0 successfully.

Result is also correct (boot to RHEL6.0 successfully) if 2*BDW CPU with force to 16 core, EIST enabled.

However, system failed to boot to OS if 1*BDW CPU and force number of cores to 18.

According to the result, it seems RHEL6.0 support max 16 cores for one CPU.

kernel version is 3.2.45 in RHEL6.0.
System works fine on RHEL7.0 ( 3.10.0-123.el7.x86_64 )

Thanks.
BR,
Mark.