runtime-telemetry: no way to disable individual experimental JFR features when emit-experimental-metrics=true

[RohitRed19]

Turning on experimental runtime metrics is all-or-nothing for JFR. When a user sets otel.instrumentation.runtime-telemetry.emit-experimental-metrics=true, all experimental JFR features are enabled together:

CONTEXT_SWITCH_METRICS
NETWORK_IO_METRICS
LOCK_METRICS
MEMORY_ALLOCATION_METRICS
There is no supported configuration option to keep experimental metrics on while disabling a subset of these JFR feature groups.

Reference: #16087 (comment)

[laurit]

Have a look at https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/runtime-telemetry/library#usage You could drop the metrics you don't want with a metric view.

[RohitRed19]

@laurit can you have a look?

[laurit]

@RohitRed19 try For now try using otel.instrumentation.runtime-telemetry.emit-experimental-telemetry instead of otel.instrumentation.runtime-telemetry.emit-experimental-metrics if you don't wish to get the jfr based metrics.
cc @trask ^^^
With old configuration options we disable the jfr based metrics

opentelemetry-java-instrumentation/instrumentation/runtime-telemetry/library/src/main/java/io/opentelemetry/instrumentation/runtimetelemetry/internal/Internal.java

Line 342 in ebc273b

Internal.setDisableAllJfrFeatures(builder, true);

but with the new ones we don't. Looks like having the jfr metrics enabled can be undesirable.

[RohitRed19]

Initially I have started the experiment with this flag otel.instrumentation.runtime-telemetry.emit-experimental-telemetry as true and haven't configured the remaining flags (including otel.instrumentation.runtime-telemetry.emit-experimental-metrics); but still able to see the JFR metrics.
Also want to understand baseEnabled is true by default right?

opentelemetry-java-instrumentation/instrumentation/runtime-telemetry/library/src/main/java/io/opentelemetry/instrumentation/runtimetelemetry/internal/Internal.java

Lines 275 to 277 in ebc273b

	if (baseEnabled) {
	configureUnified(builder, config);
	return builder.build();

[laurit]

Hopefully resolved with #18110

[RohitRed19]

Thanks a lot, @laurit and @trask!