# Semantic Conventions for JVM Metrics **Status**: [Experimental][DocumentStatus] This document describes semantic conventions for JVM metrics in OpenTelemetry. - [JVM Memory](#jvm-memory) * [Metric: `jvm.memory.usage`](#metric-jvmmemoryusage) * [Metric: `jvm.memory.committed`](#metric-jvmmemorycommitted) * [Metric: `jvm.memory.limit`](#metric-jvmmemorylimit) * [Metric: `jvm.memory.usage_after_last_gc`](#metric-jvmmemoryusage_after_last_gc) - [JVM Garbage Collection](#jvm-garbage-collection) * [Metric: `jvm.gc.duration`](#metric-jvmgcduration) - [JVM Threads](#jvm-threads) * [Metric: `jvm.thread.count`](#metric-jvmthreadcount) - [JVM Classes](#jvm-classes) * [Metric: `jvm.class.loaded`](#metric-jvmclassloaded) * [Metric: `jvm.class.unloaded`](#metric-jvmclassunloaded) * [Metric: `jvm.class.count`](#metric-jvmclasscount) - [JVM CPU](#jvm-cpu) * [Metric: `jvm.cpu.time`](#metric-jvmcputime) * [Metric: `jvm.cpu.count`](#metric-jvmcpucount) * [Metric: `jvm.cpu.recent_utilization`](#metric-jvmcpurecent_utilization) - [Very experimental](#very-experimental) * [Metric: `jvm.memory.init`](#metric-jvmmemoryinit) * [Metric: `jvm.system.cpu.utilization`](#metric-jvmsystemcpuutilization) * [Metric: `jvm.system.cpu.load_1m`](#metric-jvmsystemcpuload_1m) * [Metric: `jvm.buffer.memory.usage`](#metric-jvmbuffermemoryusage) * [Metric: `jvm.buffer.memory.limit`](#metric-jvmbuffermemorylimit) * [Metric: `jvm.buffer.count`](#metric-jvmbuffercount) ## JVM Memory **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.memory.*` ### Metric: `jvm.memory.usage` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.memory.usage` | UpDownCounter | `By` | Measure of memory used. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.memory.pool.name` | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | Recommended | | `jvm.memory.type` | string | The type of memory. | `heap`; `non_heap` | Recommended | **[1]:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). `jvm.memory.type` MUST be one of the following: | Value | Description | |---|---| | `heap` | Heap memory. | | `non_heap` | Non-heap memory | ### Metric: `jvm.memory.committed` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.memory.committed` | UpDownCounter | `By` | Measure of memory committed. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.memory.pool.name` | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | Recommended | | `jvm.memory.type` | string | The type of memory. | `heap`; `non_heap` | Recommended | **[1]:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). `jvm.memory.type` MUST be one of the following: | Value | Description | |---|---| | `heap` | Heap memory. | | `non_heap` | Non-heap memory | ### Metric: `jvm.memory.limit` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.memory.limit` | UpDownCounter | `By` | Measure of max obtainable memory. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.memory.pool.name` | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | Recommended | | `jvm.memory.type` | string | The type of memory. | `heap`; `non_heap` | Recommended | **[1]:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). `jvm.memory.type` MUST be one of the following: | Value | Description | |---|---| | `heap` | Heap memory. | | `non_heap` | Non-heap memory | ### Metric: `jvm.memory.usage_after_last_gc` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getCollectionUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getCollectionUsage--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.memory.usage_after_last_gc` | UpDownCounter | `By` | Measure of memory used, as measured after the most recent garbage collection event on this pool. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.memory.pool.name` | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | Recommended | | `jvm.memory.type` | string | The type of memory. | `heap`; `non_heap` | Recommended | **[1]:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). `jvm.memory.type` MUST be one of the following: | Value | Description | |---|---| | `heap` | Heap memory. | | `non_heap` | Non-heap memory | ## JVM Garbage Collection **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.gc.*` ### Metric: `jvm.gc.duration` This metric is [recommended][MetricRecommended]. This metric is obtained by subscribing to [`GarbageCollectionNotificationInfo`](https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/GarbageCollectionNotificationInfo.html) events provided by [`GarbageCollectorMXBean`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/GarbageCollectorMXBean.html). The duration value is obtained from [`GcInfo`](https://docs.oracle.com/javase/8/docs/jre/api/management/extension/com/sun/management/GcInfo.html#getDuration--) This metric SHOULD be specified with [`ExplicitBucketBoundaries`](https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/metrics/api.md#instrument-advice) of `[]` (single bucket histogram capturing count, sum, min, max). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.gc.duration` | Histogram | `s` | Duration of JVM garbage collection actions. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.gc.action` | string | Name of the garbage collector action. [1] | `end of minor GC`; `end of major GC` | Recommended | | `jvm.gc.name` | string | Name of the garbage collector. [2] | `G1 Young Generation`; `G1 Old Generation` | Recommended | **[1]:** Garbage collector action is generally obtained via [GarbageCollectionNotificationInfo#getGcAction()](https://docs.oracle.com/en/java/javase/11/docs/api/jdk.management/com/sun/management/GarbageCollectionNotificationInfo.html#getGcAction()). **[2]:** Garbage collector name is generally obtained via [GarbageCollectionNotificationInfo#getGcName()](https://docs.oracle.com/en/java/javase/11/docs/api/jdk.management/com/sun/management/GarbageCollectionNotificationInfo.html#getGcName()). ## JVM Threads **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.thread.*` ### Metric: `jvm.thread.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ThreadMXBean#getDaemonThreadCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ThreadMXBean.html#getDaemonThreadCount--) and [`ThreadMXBean#getThreadCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ThreadMXBean.html#getThreadCount--). Note that this is the number of platform threads (as opposed to virtual threads). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.thread.count` | UpDownCounter | `{thread}` | Number of executing platform threads. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | [`thread.daemon`](../general/attributes.md) | boolean | Whether the thread is daemon or not. | | Recommended | ## JVM Classes **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.class.*` ### Metric: `jvm.class.loaded` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ClassLoadingMXBean#getTotalLoadedClassCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ClassLoadingMXBean.html#getTotalLoadedClassCount--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.class.loaded` | Counter | `{class}` | Number of classes loaded since JVM start. | ### Metric: `jvm.class.unloaded` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ClassLoadingMXBean#getUnloadedClassCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ClassLoadingMXBean.html#getUnloadedClassCount--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.class.unloaded` | Counter | `{class}` | Number of classes unloaded since JVM start. | ### Metric: `jvm.class.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`ClassLoadingMXBean#getLoadedClassCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/ClassLoadingMXBean.html#getLoadedClassCount--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.class.count` | UpDownCounter | `{class}` | Number of classes currently loaded. | ## JVM CPU **Description:** Java Virtual Machine (JVM) metrics captured under the namespace `jvm.cpu.*` ### Metric: `jvm.cpu.time` This metric is [recommended][MetricRecommended]. This metric is obtained from [`com.sun.management.OperatingSystemMXBean#getProcessCpuTime()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getProcessCpuTime()) on HotSpot and [`com.ibm.lang.management.OperatingSystemMXBean#getProcessCpuTime()`](https://www.ibm.com/docs/api/v1/content/SSYKE2_8.0.0/openj9/api/jdk8/jre/management/extension/com/ibm/lang/management/OperatingSystemMXBean.html#getProcessCpuTime--) on J9. | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.cpu.time` | Counter | `s` | CPU time used by the process as reported by the JVM. | ### Metric: `jvm.cpu.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`Runtime#availableProcessors()`](https://docs.oracle.com/javase/8/docs/api/java/lang/Runtime.html#availableProcessors--). Note that this is always an integer value (i.e. fractional or millicores are not represented). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.cpu.count` | UpDownCounter | `{cpu}` | Number of processors available to the Java virtual machine. | ### Metric: `jvm.cpu.recent_utilization` This metric is [recommended][MetricRecommended]. This metric is obtained from [`com.sun.management.OperatingSystemMXBean#getProcessCpuLoad()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getProcessCpuLoad()) on HotSpot and [`com.ibm.lang.management.OperatingSystemMXBean#getProcessCpuLoad()`](https://www.ibm.com/docs/api/v1/content/SSYKE2_8.0.0/openj9/api/jdk8/jre/management/extension/com/ibm/lang/management/OperatingSystemMXBean.html#getProcessCpuLoad--) on J9. Note that the JVM does not provide a definition of what "recent" means. | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.cpu.recent_utilization` | Gauge | `1` | Recent CPU utilization for the process as reported by the JVM. [1] | **[1]:** The value range is [0.0,1.0]. This utilization is not defined as being for the specific interval since last measurement (unlike `system.cpu.utilization`). [Reference](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getProcessCpuLoad()). ## Very experimental **Description:** Very experimental Java Virtual Machine (JVM) metrics captured under `jvm.` ### Metric: `jvm.memory.init` This metric is [recommended][MetricRecommended]. This metric is obtained from [`MemoryPoolMXBean#getUsage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/MemoryPoolMXBean.html#getUsage--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.memory.init` | UpDownCounter | `By` | Measure of initial memory requested. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.memory.pool.name` | string | Name of the memory pool. [1] | `G1 Old Gen`; `G1 Eden space`; `G1 Survivor Space` | Recommended | | `jvm.memory.type` | string | The type of memory. | `heap`; `non_heap` | Recommended | **[1]:** Pool names are generally obtained via [MemoryPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/MemoryPoolMXBean.html#getName()). `jvm.memory.type` MUST be one of the following: | Value | Description | |---|---| | `heap` | Heap memory. | | `non_heap` | Non-heap memory | ### Metric: `jvm.system.cpu.utilization` This metric is [Opt-In][MetricOptIn]. This metric is obtained from [`com.sun.management.OperatingSystemMXBean#getSystemCpuLoad()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getSystemCpuLoad()) on Java version 8..13, [`com.sun.management.OperatingSystemMXBean#getCpuLoad()`](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getCpuLoad()) on Java version 14+, and [`com.ibm.lang.management.OperatingSystemMXBean#getSystemCpuLoad()`](https://www.ibm.com/docs/api/v1/content/SSYKE2_8.0.0/openj9/api/jdk8/jre/management/extension/com/ibm/lang/management/OperatingSystemMXBean.html) on J9. | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.system.cpu.utilization` | Gauge | `1` | Recent CPU utilization for the whole system as reported by the JVM. [1] | **[1]:** The value range is [0.0,1.0]. This utilization is not defined as being for the specific interval since last measurement (unlike `system.cpu.utilization`). [Reference](https://docs.oracle.com/en/java/javase/17/docs/api/jdk.management/com/sun/management/OperatingSystemMXBean.html#getCpuLoad()). ### Metric: `jvm.system.cpu.load_1m` This metric is [Opt-In][MetricOptIn]. This metric is obtained from [`OperatingSystemMXBean#getSystemLoadAverage()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.system.cpu.load_1m` | Gauge | `{run_queue_item}` | Average CPU load of the whole system for the last minute as reported by the JVM. [1] | **[1]:** The value range is [0,n], where n is the number of CPU cores - or a negative number if the value is not available. This utilization is not defined as being for the specific interval since last measurement (unlike `system.cpu.utilization`). [Reference](https://docs.oracle.com/en/java/javase/17/docs/api/java.management/java/lang/management/OperatingSystemMXBean.html#getSystemLoadAverage()). ### Metric: `jvm.buffer.memory.usage` This metric is [recommended][MetricRecommended]. This metric is obtained from [`BufferPoolMXBean#getMemoryUsed()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/BufferPoolMXBean.html#getMemoryUsed--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.buffer.memory.usage` | UpDownCounter | `By` | Measure of memory used by buffers. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.buffer.pool.name` | string | Name of the buffer pool. [1] | `mapped`; `direct` | Recommended | **[1]:** Pool names are generally obtained via [BufferPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/BufferPoolMXBean.html#getName()). ### Metric: `jvm.buffer.memory.limit` This metric is [recommended][MetricRecommended]. This metric is obtained from [`BufferPoolMXBean#getTotalCapacity()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/BufferPoolMXBean.html#getTotalCapacity--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.buffer.memory.limit` | UpDownCounter | `By` | Measure of total memory capacity of buffers. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.buffer.pool.name` | string | Name of the buffer pool. [1] | `mapped`; `direct` | Recommended | **[1]:** Pool names are generally obtained via [BufferPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/BufferPoolMXBean.html#getName()). ### Metric: `jvm.buffer.count` This metric is [recommended][MetricRecommended]. This metric is obtained from [`BufferPoolMXBean#getCount()`](https://docs.oracle.com/javase/8/docs/api/java/lang/management/BufferPoolMXBean.html#getCount--). | Name | Instrument Type | Unit (UCUM) | Description | | -------- | --------------- | ----------- | -------------- | | `jvm.buffer.count` | UpDownCounter | `{buffer}` | Number of buffers in the pool. | | Attribute | Type | Description | Examples | Requirement Level | |---|---|---|---|---| | `jvm.buffer.pool.name` | string | Name of the buffer pool. [1] | `mapped`; `direct` | Recommended | **[1]:** Pool names are generally obtained via [BufferPoolMXBean#getName()](https://docs.oracle.com/en/java/javase/11/docs/api/java.management/java/lang/management/BufferPoolMXBean.html#getName()). [DocumentStatus]: https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/document-status.md [MetricOptIn]: https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/metrics/metric-requirement-level.md#opt-in [MetricRecommended]: https://github.com/open-telemetry/opentelemetry-specification/tree/v1.26.0/specification/metrics/metric-requirement-level.md#recommended