3.2. Performance

The single-node claims implementation which is the basis of the NUMA claims v4 series and the multi-node claim sets design forms the groundwork for the NUMA design and implementation in XenServer 9.

An early version of it is available as the XenServer XS9 preview release: https://www.xenserver.com/downloads/xs9-preview. The performance of this release has been tested in real customer environments with customer workloads.

On dual-socket Intel servers, the average aggregate CPU usage across all VMs at peak times (peak user load) was ~16% less than with XenServer 8.4 (overall average at all times ~8.5% less) compared to the previous release, which is a significant improvement in CPU efficiency for memory-intensive workloads, attributed to the improved NUMA placement enabled by NUMA-aware claims.

The customer’s response time metric from their application, which is the key measure the customer uses for end user observed performance, showed an ~8% improvement, matching the improvement in average CPU usage.

These numbers were observed using Intel dual-socket servers. The performance benefits with AMD servers (judging by preliminary tests) are expected to be considerably higher than the results with dual-socket Intel servers.

The multi-node claim sets design is expected to extend these benefits to configurations that require claiming memory from multiple NUMA nodes adjacent to each other for optimal performance.