Runtime instrumentation supports float64 runtime/metrics

[w-h-a]

Problem Statement

The current runtime instrumentation supports some int64 and float64Histogram metrics from the runtime/metrics standard lib. Some of the metrics in the standard lib such as /sync/mutex/wait/total:seconds are float64. What would be required to support such metrics in the runtime instrumentation?

Proposed Solution

I am not entirely sure of a solution yet. It seems straightforward to add to the current runtime instrumentation code, and I'd be happy to contribute. However, I want to proceed in line with OTEL and the code owners of the runtime instrumentation. I'm hoping to start a conversation on how we could move forward. Any OTEL spec docs that are blocking here would be very helpful to me.

Alternatives

If nothing else, more documentation on why specific runtime/metrics are not provided would be helpful.

Prior Art

Not sure.

Additional Context

https://pkg.go.dev/runtime/[email protected]

[dmathieu]

The runtime metrics we provided are documented in semantic conventions.
See https://github.com/open-telemetry/semantic-conventions/blob/main/docs/runtime/go-metrics.md

Before we can add new metrics, we'd need to update the semconvs.

[w-h-a]

Thanks for the pointer. I will read up!

[w-h-a]

Opened an issue in the semantic-conventions repo: open-telemetry/semantic-conventions#2161