RFR: 8058935: CPU detection gives 0 cores per cpu, 2 threads per core in Amazon EC2 environment
vladimir.kempik at oracle.com
Mon Nov 17 16:20:58 UTC 2014
Please review patch adding sanity check to cores_per_cpu():
Few months ago we've got reports of java crashing in amazon ec2
enviroment (they use Xen).
JVM args was used to make the crash: -XX:+UnlockCommercialFeatures
After investigation I think the crash could only have happened if
support_processor_topology() returned true and
_cpuid_info.tpl_cpuidB1_ebx.bits.logical_cpus was zero.
I wasn't able to reproduce the bug on amazon ec2 cloud in present days.
The patch adds sanity check, if cpu topology was used and resulted in 0
cores per cpu, then fallback to non-topology variant, which can't result
in 0 cores per cpu.
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