:_mod-docs-content-type: REFERENCE [id="ref_rn-qdocs-1395-opentelemetry-metrics-differ-on-semeru"] = OpenTelemetry: JVM metrics differ on IBM Semeru Runtimes In the current release, JVM metrics exported by Quarkus Micrometer to OpenTelemetry differ between IBM Semeru Runtimes and OpenJDK HotSpot. The metric set and memory pool breakdowns differ across JVMs because the OpenTelemetry conventions obtain pool names from `MemoryPoolMXBean`, and each JVM defines different pools. Dashboards, alerts, and queries built for HotSpot can fail to match Semeru outputs, and you need to adjust them. For example, with the `jvm.memory.used` metric, HotSpot commonly reports pools such as `G1 Survivor Space`, `G1 Eden Space`, `G1 Old Gen`, `Metaspace`, and `CodeHeap 'profiled nmethods'`. Semeru reports pools such as `class storage`, `JIT code cache`, `nursery-allocate`, and `tenured-SOA`. Review your metric filters and attribute selectors such as `jvm.memory.pool.name` and `jvm.memory.type` to account for JVM-specific pool names and for pools that exist only on one JVM. When you enable the bridge with `quarkus-micrometer-opentelemetry`, OpenTelemetry auto-instrumentation for JVM metrics is disabled by default, and Micrometer collects the JVM metrics. For more information, see: * Quarkus link: https://quarkus.io/guides/observability [Observability] * Quarkus link: https://quarkus.io/guides/telemetry-micrometer [Micrometer metrics] * Quarkus link: https://quarkus.io/guides/telemetry-micrometer-to-opentelemetry [Micrometer and OpenTelemetry extension] * link: https://opentelemetry.io/docs/specs/semconv/runtime/jvm-metrics [JVM metrics semantic conventions] * link: https://eclipse.dev/openj9/docs/api/jdk11/jdk.management/com/ibm/lang/management/MemoryPoolMXBean.html [OpenJ9 memory pool names (MemoryPoolMXBean)] * link: https://github.com/open-telemetry/opentelemetry-java-instrumentation/tree/main/instrumentation/runtime-telemetry/runtime-telemetry-java17/library [OpenTelemetry runtime telemetry (Java 17) library] // https://issues.redhat.com/browse/QDOCS-1395 // SME: Martin Ocenas, Bruno Baptista // Observability // Known issue // include::rn/ref_rn-qdocs-1395-opentelemetry-metrics-differ-on-semeru.adoc[leveloffset=+2]