Power optimization is a prime concern for large-scale OSP deployments and data center operators. With the increasing scale at the core sites and restricted power capacity at the edge and far-edge sites, power budgets are limited and constrained. But at the same time service providers and data center operators still aspire to high data plane performance and data plane acceleration with minimal power penalty. 

One of the data plane acceleration technologies in the OSP domain is OVS-DPDK. Although OVS-DPDK provides the desired data plane acceleration, it does so at the expense of additional CPU processing and additional CPU cores and memory. This in turn impacts power consumption. Given the limited power budgets, Service Providers and data center operators are looking for innovative ways to optimize the power consumption.

Servers hosting the applications and network functions are not always busy or processing data. At times, the provisioned servers do not have the workloads deployed at capacity or not all the CPU cores are used. This presents an opportunity to move the CPU to certain states that consume less power. 

C-states enable shutting down of idle subsystems of CPU cores or moving them to sleep states where there is minimal power consumption whereas p-states enable lowering the frequency of for the CPU cores to reduce the power consumption when the incoming packet rates are low. 

Requirement-1:

• The expectation is to move to a “custom profile” post-introspection/provisioning step for the servers with a subset of unallocated cores. The expectation is for OSP to provide the necessary interfaces to achieve this saving to enable these use cases:
  • VZ’s data center devops intend to use a specific tuned profile for CPU hotplug to disable cores that are unpinned currently and not needed now, nor likely ever to be needed due to their very static VM placements. 
  • VZ’s data center devops intend to use CPU p-state & c-state to say dial down a core spinning at max frequency say 2.2GHz if the associated VNF+NIC etc can only push through packets at a rate that could be matched by a core running at say 800MHz

Requirement-2:

• Using Telemetry to feed into smarter placement decisions to achieve dynamic power management profiles

Power Management Blog (C-States, P-States)

DPDK Power Optimization Reference

Verizon Power Requirements

C-State BZ