Which design approach is an example of the performance efficiency pillar in the AWS Well-Architected Framework?

Using serverless architectures is a prime example of performance efficiency because it automatically scales compute resources up and down based on demand, eliminating the need for manual provisioning and ensuring optimal resource utilization. This dynamic scaling directly contributes to efficient performance by matching resources to workload needs. Scaling horizontally is a technique that contributes to performance efficiency but is a broader concept applicable to many architectural styles, not exclusively serverless. Measuring the cost of workloads is related to the Cost Optimization pillar. Using managed services can improve performance efficiency by offloading operational overhead, but it's a general best practice across multiple pillars, not a direct example of a performance efficiency design approach in the same way serverless architectures are.