Log on to the Real-time Monitoring Service (RMS) console. In the left-side navigation pane, click Application Monitoring. Click the My Applications or All Applications tab. Then, click the name of an application. The details page of the application appears. This topic describes the Java virtual machine (JVM) metrics that you can view when application details are displayed in a visualized manner.
For more information about custom configurations of metrics, see Application overview.
The JVM metrics described in this topic are provided by RMS. However, only the most frequently used metrics are displayed in a visualized manner in the RMS console.
GC
Metric |
Description |
ygc_count |
The number of times young garbage collection (YGC) is performed. |
ygc_time |
The total time consumed by YGC. Unit: seconds. |
fgc_count |
The number of times full GC (FGC) is performed. The value is inaccurate for concurrent mark sweep (CMS) FGC. |
fgc_time |
The total time consumed by FGC. Unit: seconds. The value is inaccurate for CMS FGC. |
tlab_alloc |
The total capacity allocated to the thread local allocation buffer (TLAB). |
Runtime
Metric |
Description |
thread_started |
The number of started threads. |
thread_live |
The number of alive threads. |
thread_daemon |
The number of daemon threads. |
thread_live_peak |
The peak number of alive threads. |
safepoints |
The number of safepoints. |
safepoint_time |
The time consumed by the safepoint operation. |
safepoint_sync_time |
The total time consumed by safepoint synchronization. |
application_time |
The total running time of the application. |
parks |
The number of parks. |
notifications |
The number of times notifications are sent. |
mon_extant |
To be supplemented. |
inflations |
The number of times lock inflation occurs. |
futile_wakeups |
To be supplemented. |
deflations |
To be supplemented. |
contented_lock_attemps |
To be supplemented. |
Eden space
Metric |
Description |
eden_used |
The used capacity of the Eden space. |
eden_capacity |
The current capacity of the Eden space. You can apply for expansion of the capacity. |
eden_max |
The total capacity of the Eden space, which cannot be expanded. |
Old generation space
Metric |
Description |
old_used |
The used capacity of the old generation space. |
old_capacity |
The current capacity of the old generation space. You can apply for expansion of the capacity. |
old_max |
The total capacity of the old generation space, which cannot be expanded. |
Metaspace
The metaspace involves many metrics. In most cases, you need to pay attention only to the following metrics: meta_used, meta_capacity, meta_util, and meta_rutil.
In addition, Java Development Kit (JDK) V8.7.12_fp1 or later is required for chunk-related metrics.
Metric |
Description |
meta_used |
The used capacity of the metaspace. |
meta_capacity |
The current capacity of the metaspace. You can apply for expansion of the capacity. |
meta_util |
The capacity usage of the metaspace, regardless of the chunk usage. The capacity usage is the percentage of meta_used to meta_capacity. |
meta_rutil |
The actual capacity usage of the metaspace, considering the chunk usage. The actual capacity usage is the percentage of meta_chunks_used to meta_capacity. |
compressedclass_used |
The used capacity of the compressed class space. This capacity is included in the capacity specified by the sun.gc.metaspace.used metric. |
compressedclass_capacity |
The capacity of the compressed class space. This capacity is included in the capacity specified by the sun.gc.metaspace.capacity metric. |
meta_chunks_free |
The total capacity of idle chunks in the metaspace. |
meta_chunks_used |
The total capacity of used chunks in the metaspace. FGC is triggered when the total capacity of used chunks in the metaspace approaches the maximum capacity of the metaspace. |
compressedclass_chunks_free |
The total capacity of idle chunks in the compressed class space. This capacity is included in the capacity specified by the com.alibaba.metaspace.freeChunksTotal metric. |
compressedclass_chunks_used |
The total capacity of used chunks in the compressed class space. This capacity is included in the capacity specified by the com.alibaba.metaspace.usedChunksTotal metric. |