Your JVM may experience performance issues due to an excessive number of Garbage Collection (GC) threads. These can lead to increased context switching, higher CPU consumption, and degraded application response time. The default thread count is based on the number of CPUs, but you can manually adjust it using specific JVM arguments to optimize performance without introducing new problems.
Automatic garbage collection in programming languages like Golang, Java, and Python streamlines memory management but can lead to high CPU usage. This article discusses methods to measure CPU consumption due to garbage collection, including GC log analysis, monitoring tools, and insight from GC threads, enabling optimizations for improved application performance.
The GC log tracks the time taken for garbage collection events, including 'real' (total elapsed time), 'user' (CPU time in user-mode), and 'sys' (CPU time in kernel). User time typically exceeds sys time, but anomalies indicate OS issues, VM overload, memory constraints, or disk I/O pressure. Address these for optimal performance.
GC logs detail the time taken for GC events, reporting 'user', 'sys', and 'real' times. 'Real' time is the elapsed clock time, while 'user' and 'sys' times reflect CPU time in user-mode and kernel, respectively. Real time can exceed user + sys time due to heavy I/O activity or lack of CPU, indicating potential performance issues.
Long GC pauses hinder application performance, impacting SLAs and user experience. Key causes include high object creation rates, undersized young generations, unsuitable GC algorithms, excessive memory swapping, and inadequate GC threads. Solutions involve optimizing object creation, adjusting young generation size, and selecting efficient GC strategies to minimize pauses and enhance stability.