There is currently a gaping void in the market when it comes to objective performance measures for real-time ray-tracing, but that's a void that benchmarking specialists UL (formerly FutureMark) are seeking to at least partially fill with an addition to their 3DMark suite. From January 8th 2019 the Port Royal Ray Tracing Benchmark will be the first DirectX ray-tracing benchmark available to consumers, developed with input from NVIDIA, AMD, Microsoft and Intel.
Consumers who already have access to the Advanced or Professional editions of 3DMark 2018 will be able to purchase the additional benchmarking tool for just $2.99 (USD) or their regional equivalent on January 8th. From that point on, 3DMark Advanced Edition with Port Royal will be available for $29.99.
Details for the benchmark have yet to be fully disclosed, but it appears it will run natively at 1440p. System drivers will need to support DXR Ray-Tracing, and some level of hardware acceleration will likely be necessary to generate useful results. Ul also claim that the benchmark will offer performance level indicators for games with real-time ray tracing running on compatible systems, a fact that may be especially useful as a more varied hardware ecosystem for ray tracing comes to fruition.
More information is available here.