GC 日志 - VM 操作事件 - 如何跟踪它们

GC logs - VM operation events - how to track them

我正在使用 GCViewer 检查一些 GC 日志。（请查看下方截图）

我收到很多似乎与 "vm operation events(application stopped...)" 有关的高停顿（红色矩形）。这些似乎与常规和完整的 GC 停止不同。

我怎样才能知道哪些操作触发了停止事件？（是否有 JVM 标志？）
它们与垃圾回收有区别吗？就 GCViewer 而言，Full GC Pauses + GC Pauses != Total Pause

将 -XX:+PrintSafepointStatistics –XX:PrintSafepointStatisticsCount=1 添加到您的 VM 选项，这应该将有关 non-GC 安全点的信息添加到日志中。

-XX:LogFile=/path/to/file -XX:+LogVMOutput 用于记录到文件。

添加 -XX:+PrintSafepointStatistics –XX:PrintSafepointStatisticsCount=1 将提供有关触发停止事件的操作的信息。

When safepoints are used?

Below are few reasons for HotSpot JVM to initiate a safepoint:

Garbage collection pauses

Code deoptimization

Flushing code cache

Class redefinition (e.g. hot swap or instrumentation)

Biased lock revocation

Various debug operation (e.g. deadlock check or stacktrace dump)

对于将日志写入文件，这取决于您使用的 VM 版本。

对于所有 Java 版本： Java 8 Docs.

-Xloggc:filename

Sets the file to which verbose GC events information should be redirected for logging. The information written to this file is similar to the output of -verbose:gc with the time elapsed since the first GC event preceding each logged event. The -Xloggc option overrides -verbose:gc if both are given with the same java command.

来自 Java 版本 8：

-XX:LogFile=path

Sets the path and file name where log data is written. By default, the file is created in the current working directory, and it is named hotspot.log.

GC 日志 - VM 操作事件 - 如何跟踪它们

GC logs - VM operation events - how to track them

java

garbage-collection

jvm