GC 日志相关选项

布满荆棘的人生 2022-09-10 06:24 191阅读 0赞

# 一 常用选项 #

> \-XX:+PrintGC <==> -verbose:gc  打印简要日志信息，独立使用
> 
> \-XX:+PrintGCDetails            打印详细日志信息，独立使用
> 
> \-XX:+PrintGCTimeStamps  打印程序启动到GC发生的时间，搭配 -XX:+PrintGCDetails 使用，不可以独立使用
> 
> \-XX:+PrintGCDateStamps  打印GC发生时的时间戳，搭配 -XX:+PrintGCDetails 使用，不可以独立使用
> 
> \-XX:+PrintHeapAtGC  打印 GC 前后的堆信息，独立使用
> 
> \-Xloggc:<file> 输出 GC 到指定路径下的文件中

# 二 其他选项 #

> \-XX:+TraceClassLoading  监控类的加载
> 
> \-XX:+PrintGCApplicationStoppedTime  打印 GC 时线程的停顿时间
> 
> \-XX:+PrintGCApplicationConcurrentTime  打印垃圾收集之前应用未中断的执行时间
> 
> \-XX:+PrintReferenceGC 打印回收了多少种不同引用类型的引用
> 
> \-XX:+PrintTenuringDistribution  打印 JVM 在每次 MinorGC 后当前使用的 Survivor 中对象的年龄分布
> 
> \-XX:+UseGCLogFileRotation 启用 GC 日志文件的自动转储
> 
> \-XX:NumberOfGCLogFiles=1  设置 GC 日志文件的循环数目
> 
> \-XX:GCLogFileSize=1M  设置 GC 日志文件的大小

# 三 实战 #

**1 代码**

package chapter04;
    
    import java.util.ArrayList;
    /**
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -verbose:gc
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGC
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCDateStamps
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintHeapAtGC
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintHeapAtGC -XX:+PrintGCDetails -Xloggc:d:/heaplog.log
    * -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCApplicationStoppedTime
    */
    public class GCLogTest {
        public static void main(String[] args) {
            ArrayList<byte[]> list = new ArrayList<>();
    
    
            for (int i = 0; i < 500; i++) {
                byte[] arr = new byte[1024 * 100];// 100kb
                list.add(arr);
                try {
                    Thread.sleep(20);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    }

**2 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -verbose:gc 启动**

> \[GC (Allocation Failure)  16294K->14546K(59392K), 0.0039367 secs\]
> 
> \[GC (Allocation Failure)  30894K->30517K(59392K), 0.0055465 secs\]
> 
> \[Full GC (Ergonomics)  30517K->30300K(59392K), 0.0108135 secs\]
> 
> \[Full GC (Ergonomics)  46584K->46402K(59392K), 0.0069119 secs\]

**3 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGC**

> \[GC (Allocation Failure)  16384K->14378K(59392K), 0.0042745 secs\]
> 
> \[GC (Allocation Failure)  30698K->30688K(59392K), 0.0048966 secs\]
> 
> \[Full GC (Ergonomics)  30688K->30561K(59392K), 0.0122676 secs\]
> 
> \[Full GC (Ergonomics)  46905K->46564K(59392K), 0.0098682 secs\]

**4 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails**

> \[GC (Allocation Failure) \[PSYoungGen: 16384K->2036K(18432K)\] 16384K->14422K(59392K), 0.0043724 secs\] \[Times: user=0.00 sys=0.00, real=0.00 secs\]
> 
> \[GC (Allocation Failure) \[PSYoungGen: 18356K->2020K(18432K)\] 30742K->30672K(59392K), 0.0046265 secs\] \[Times: user=0.02 sys=0.08, real=0.00 secs\]
> 
> \[Full GC (Ergonomics) \[PSYoungGen: 2020K->0K(18432K)\] \[ParOldGen: 28652K->30561K(40960K)\] 30672K->30561K(59392K), \[Metaspace: 3726K->3726K(1056768K)\], 0.0156724 secs\] \[Times: user=0.00 sys=0.00, real=0.02 secs\]
> 
> \[Full GC (Ergonomics) \[PSYoungGen: 16343K->6100K(18432K)\] \[ParOldGen: 30561K->40463K(40960K)\] 46905K->46564K(59392K), \[Metaspace: 3727K->3727K(1056768K)\], 0.0097613 secs\] \[Times: user=0.01 sys=0.00, real=0.01 secs\]
> 
> Heap
> 
> PSYoungGen      total 18432K, used 10679K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 65% used \[0x00000000fec00000,0x00000000ff66dc00,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 40463K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 98% used \[0x00000000fc400000,0x00000000feb83e40,0x00000000fec00000)
> 
> Metaspace       used 3733K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 408K, capacity 428K, committed 512K, reserved 1048576K

**5 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCTimeStamps**

> 4.396: \[GC (Allocation Failure) \[PSYoungGen: 16384K->2036K(18432K)\] 16384K->14406K(59392K), 0.0047065 secs\] \[Times: user=0.00 sys=0.00, real=0.00 secs\]
> 
> 9.561: \[GC (Allocation Failure) \[PSYoungGen: 18357K->1960K(18432K)\] 30726K->30740K(59392K), 0.0063010 secs\] \[Times: user=0.00 sys=0.01, real=0.01 secs\]
> 
> 9.567: \[Full GC (Ergonomics) \[PSYoungGen: 1960K->0K(18432K)\] \[ParOldGen: 28780K->30561K(40960K)\] 30740K->30561K(59392K), \[Metaspace: 3726K->3726K(1056768K)\], 0.0168554 secs\] \[Times: user=0.06 sys=0.00, real=0.02 secs\]
> 
> 14.630: \[Full GC (Ergonomics) \[PSYoungGen: 16343K->6100K(18432K)\] \[ParOldGen: 30561K->40463K(40960K)\] 46905K->46564K(59392K), \[Metaspace: 3726K->3726K(1056768K)\], 0.0055275 secs\] \[Times: user=0.00 sys=0.00, real=0.01 secs\]
> 
> Heap
> 
> PSYoungGen      total 18432K, used 10679K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 65% used \[0x00000000fec00000,0x00000000ff66dc00,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 40463K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 98% used \[0x00000000fc400000,0x00000000feb83f18,0x00000000fec00000)
> 
> Metaspace       used 3732K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 408K, capacity 428K, committed 512K, reserved 1048576K

**6 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCDetails -XX:+PrintGCDateStamps  **

> 2021-09-06T08:44:49.453+0800: \[GC (Allocation Failure) \[PSYoungGen: 16384K->2020K(18432K)\] 16384K->14426K(59392K), 0.0060231 secs\] \[Times: user=0.00 sys=0.00, real=0.01 secs\]
> 
> 2021-09-06T08:44:54.610+0800: \[GC (Allocation Failure) \[PSYoungGen: 18341K->1996K(18432K)\] 30746K->30712K(59392K), 0.0068602 secs\] \[Times: user=0.00 sys=0.00, real=0.01 secs\]
> 
> 2021-09-06T08:44:54.617+0800: \[Full GC (Ergonomics) \[PSYoungGen: 1996K->0K(18432K)\] \[ParOldGen: 28716K->30565K(40960K)\] 30712K->30565K(59392K), \[Metaspace: 3725K->3725K(1056768K)\], 0.0156272 secs\] \[Times: user=0.02 sys=0.00, real=0.01 secs\]
> 
> 2021-09-06T08:44:59.793+0800: \[Full GC (Ergonomics) \[PSYoungGen: 16315K->6000K(18432K)\] \[ParOldGen: 30565K->40864K(40960K)\] 46881K->46864K(59392K), \[Metaspace: 3726K->3726K(1056768K)\], 0.0149928 secs\] \[Times: user=0.06 sys=0.02, real=0.02 secs\]
> 
> Heap
> 
> PSYoungGen      total 18432K, used 10608K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 64% used \[0x00000000fec00000,0x00000000ff65c3c0,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 40864K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 99% used \[0x00000000fc400000,0x00000000febe8030,0x00000000fec00000)
> 
> Metaspace       used 3732K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 408K, capacity 428K, committed 512K, reserved 1048576K

**7 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintHeapAtGC**

> \# (full 0) 表示非 Full GC
> 
> \{Heap before GC invocations=1 (full 0):
> 
> PSYoungGen      total 18432K, used 16384K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 100% used \[0x00000000fec00000,0x00000000ffc00000,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 0K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 0% used \[0x00000000fc400000,0x00000000fc400000,0x00000000fec00000)
> 
> Metaspace       used 3725K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> Heap after GC invocations=1 (full 0):
> 
> PSYoungGen      total 18432K, used 2020K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 0% used \[0x00000000fec00000,0x00000000fec00000,0x00000000ffc00000)
> 
>   from space 2048K, 98% used \[0x00000000ffc00000,0x00000000ffdf9110,0x00000000ffe00000)
> 
>   to   space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
> ParOldGen       total 40960K, used 12401K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 30% used \[0x00000000fc400000,0x00000000fd01c760,0x00000000fec00000)
> 
> Metaspace       used 3725K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> \}
> 
> \# (full 0) 表示非 Full GC
> 
> \{Heap before GC invocations=2 (full 0):
> 
> PSYoungGen      total 18432K, used 18341K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 99% used \[0x00000000fec00000,0x00000000ffbf0310,0x00000000ffc00000)
> 
>   from space 2048K, 98% used \[0x00000000ffc00000,0x00000000ffdf9110,0x00000000ffe00000)
> 
>   to   space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
> ParOldGen       total 40960K, used 12401K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 30% used \[0x00000000fc400000,0x00000000fd01c760,0x00000000fec00000)
> 
> Metaspace       used 3726K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> Heap after GC invocations=2 (full 0):
> 
> PSYoungGen      total 18432K, used 2020K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 0% used \[0x00000000fec00000,0x00000000fec00000,0x00000000ffc00000)
> 
>   from space 2048K, 98% used \[0x00000000ffe00000,0x00000000ffff9110,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 28712K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 70% used \[0x00000000fc400000,0x00000000fe00a190,0x00000000fec00000)
> 
> Metaspace       used 3726K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> \}
> 
> \# (full 1) 表示第一次 Full GC
> 
> \{Heap before GC invocations=3 (full 1):
> 
> PSYoungGen      total 18432K, used 2020K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 0% used \[0x00000000fec00000,0x00000000fec00000,0x00000000ffc00000)
> 
>   from space 2048K, 98% used \[0x00000000ffe00000,0x00000000ffff9110,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 28712K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 70% used \[0x00000000fc400000,0x00000000fe00a190,0x00000000fec00000)
> 
> Metaspace       used 3726K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> Heap after GC invocations=3 (full 1):
> 
> PSYoungGen      total 18432K, used 0K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 0% used \[0x00000000fec00000,0x00000000fec00000,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 30562K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 74% used \[0x00000000fc400000,0x00000000fe1d8918,0x00000000fec00000)
> 
> Metaspace       used 3726K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> \}
> 
> \# (full 2) 表示第二次 Full GC
> 
> \{Heap before GC invocations=4 (full 2):
> 
> PSYoungGen      total 18432K, used 16315K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 99% used \[0x00000000fec00000,0x00000000ffbeefa0,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 30562K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 74% used \[0x00000000fc400000,0x00000000fe1d8918,0x00000000fec00000)
> 
> Metaspace       used 3726K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> Heap after GC invocations=4 (full 2):
> 
> PSYoungGen      total 18432K, used 6000K \[0x00000000fec00000, 0x0000000100000000, 0x0000000100000000)
> 
>   eden space 16384K, 36% used \[0x00000000fec00000,0x00000000ff1dc3c0,0x00000000ffc00000)
> 
>   from space 2048K, 0% used \[0x00000000ffe00000,0x00000000ffe00000,0x0000000100000000)
> 
>   to   space 2048K, 0% used \[0x00000000ffc00000,0x00000000ffc00000,0x00000000ffe00000)
> 
> ParOldGen       total 40960K, used 40863K \[0x00000000fc400000, 0x00000000fec00000, 0x00000000fec00000)
> 
>   object space 40960K, 99% used \[0x00000000fc400000,0x00000000febe7f58,0x00000000fec00000)
> 
> Metaspace       used 3726K, capacity 4536K, committed 4864K, reserved 1056768K
> 
>   class space    used 407K, capacity 428K, committed 512K, reserved 1048576K
> 
> \}

**8 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintHeapAtGC -XX:+PrintGCDetails -Xloggc:d:/heaplog.log**

![watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16][]

**9 设置为 -Xms60m -Xmx60m -XX:SurvivorRatio=8 -XX:+PrintGCApplicationStoppedTime**

> Total time for which application threads were stopped: 0.0001415 seconds, Stopping threads took: 0.0000461 seconds
> 
> Total time for which application threads were stopped: 0.0000912 seconds, Stopping threads took: 0.0000316 seconds
> 
> Total time for which application threads were stopped: 0.0054704 seconds, Stopping threads took: 0.0000278 seconds
> 
> Total time for which application threads were stopped: 0.0208119 seconds, Stopping threads took: 0.0000492 seconds
> 
> Total time for which application threads were stopped: 0.0058309 seconds, Stopping threads took: 0.0000393 seconds

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAY2hlbmdxaXVtaW5n_size_20_color_FFFFFF_t_70_g_se_x_16]: /images/20220829/2966aac024554ba1bf5b81377829ff0c.png