Hi All
We have 2 Oracle VM servers with the following configuration:
2 Sockets
each socket contains = 8 cores
each core = 2 threads
16 cores = 32 threads on each server and 64 threads in total
We need to pin the CPU to physical cores in order to avoid licensing issues. We have 3 CPU license with intel multiplication factor 0.5 it equals to 6 cores and have divided these cores to 3 to 4 databases. In production we have assigned 4 CPUs in the guest VM which is basically 2 cores, i have few queries, request the experts to please provide some suggestions:
1. Currently the performance of production is excellent on 2 core but by pinning the CPUs to cores will it have any impact on performance? every time when i execute the command "xm vcpu-list 1" it shows different CPUs on soft portioning, so it is keep on changing the cores and scheduling the request to available cores, but by pinning it on particular core will it have any performance degradation?
2. The document "https://ericsteed.wordpress.com/2015/05/06/oracle-vm-hard-partitioning-potential-performance-issues/" suggest that even if hyper threading is enabled 4 CPUs to be assigned only to 2 cores to limit the license but: (Point 3)
3. Document "http://mokumsolutions.com/hard-and-soft-partitioning-oracle-vm" says "Oracle VM’s default CPU scheduler is the credit scheduler. The credit scheduler uses a credit/debit system to fairly share CPU resources between virtual machines. Credits are assigned to each running virtual machine, along with the allocated fraction of CPU resources. The credit scheduler continually increments/decrements credits from running virtual machines, which is how the credit scheduler balances CPU resources. In many ways, the credit scheduler is like the Linux scheduler. The Linux scheduler is used as the default CPU scheduler with the KVM hypervisor. Both schedulers can preempt processes as needed while trying to ensure proportional fair share allocations. The default behavior of the credit scheduler is to bind each virtual machine CPU to a separate physical core. For example, when you create a virtual machine with two CPUs, the credit scheduler will map the two virtual machine CPUs to two physical cores. So when pinning virtual machine CPUs, we follow the credit scheduler’s default behavior of mapping virtual machine CPUs to an Oracle VM Server’s CPU cores" --> This means each thread should be assigned to different core this is how default scheduler works? what is the right path?
Help please
Thank you
Regards
shahrukh