正文
先说一下结果
1. Linux的内存分配是惰性分配的. APP申明了 kernel并不会立即进行初始化和使用.
2. JVM的内存主要分为, 堆区, 非堆区, 以及jvm使用的其他内存. 比如直接内存等.
3. top看到的内存与pmap 查询出来的内存基本一样. top的RES和pmap的RSS基本相同.
4. 堆区如果进行了合理的设置. 占用RSS或者是RES的比率在 70-77左右.
5. 如果使用的功能比较集中, 可能codecache等内存使用量会少, 堆区占比会高
如果全部功能遍历, 那么codecache 以及本地内存的缓存等就会比较大, 堆区的占比就会小.
6. 如果使用容器的话 75% 应该算是一个基本合理的数值.
摘要
最近中午帮某项目写docker下的启动脚本.
自己定义了几个参数. 但是感觉不太放心
怕出现因为堆外内存导致OOM的问题
撑着有一个bug 需要不停的重启服务. 我就简单学习总结了下.
主要用的工具其实就3类
1. jinfo,jcmd等命令查看JVM的信息.
增加native_memory_track的设置. 查看summary等信息.
2. pmap 从操作系统层查看内存的分配情况.
3. top 等命令查看进程状态的信息.
启动之前的结果
[root@centos7ver2009 gscloud]# jinfo 16732
Attaching to process ID 16732, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.222-b10
Java System Properties:
caf.startup.server.path.name = server
java.runtime.name = OpenJDK Runtime Environment
hibernate.jdbc.time_zone = Asia/Shanghai
java.vm.version = 25.222-b10
sun.boot.library.path = /gscloud/server/runtime/java/x86_64-linux/jre/lib/amd64
java.protocol.handler.pkgs = org.springframework.boot.loader
LOG_FILE_MAX_SIZE = 5MB
java.vendor.url = http://java.oracle.com/
java.vm.vendor = AdoptOpenJDK
path.separator = :
file.encoding.pkg = sun.io
java.vm.name = OpenJDK 64-Bit Server VM
sun.os.patch.level = unknown
sun.java.launcher = SUN_STANDARD
user.country = CN
user.dir = /gscloud
java.vm.specification.name = Java Virtual Machine Specification
PID = 16732
java.runtime.version = 1.8.0_222-b10
java.awt.graphicsenv = sun.awt.X11GraphicsEnvironment
os.arch = amd64
java.endorsed.dirs = /gscloud/server/runtime/java/x86_64-linux/jre/lib/endorsed
CONSOLE_LOG_CHARSET = UTF-8
spring.profiles.active = prod
line.separator =
java.io.tmpdir = /tmp
java.vm.specification.vendor = Oracle Corporation
os.name = Linux
FILE_LOG_CHARSET = UTF-8
sun.jnu.encoding = UTF-8
java.library.path = /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
spring.beaninfo.ignore = true
java.class.version = 52.0
java.specification.name = Java Platform API Specification
sun.management.compiler = HotSpot 64-Bit Tiered Compilers
os.version = 3.10.0-1160.el7.x86_64
user.home = /root
user.timezone = Asia/Shanghai
LOGBACK_ROLLINGPOLICY_MAX_FILE_SIZE = 5242880
catalina.useNaming = false
java.awt.printerjob = sun.print.PSPrinterJob
file.encoding = UTF-8
java.specification.version = 1.8
catalina.home = /tmp/tomcat.5200.6719909097640900997
user.name = root
java.class.path = ./server/runtime/caf-bootstrap.jar
com.sun.org.apache.xml.internal.dtm.DTMManager = com.sun.org.apache.xml.internal.dtm.ref.DTMManagerDefault
loader.path = ./server/runtime/3rd,./server/runtime/libs
server.runtime.path.name = /gscloud/server
java.vm.specification.version = 1.8
sun.arch.data.model = 64
sun.java.command = ./server/runtime/caf-bootstrap.jar --spring.config.location=./server/runtime/
java.home = /gscloud/server/runtime/java/x86_64-linux/jre
user.language = zh
java.specification.vendor = Oracle Corporation
awt.toolkit = sun.awt.X11.XToolkit
java.vm.info = mixed mode
java.version = 1.8.0_222
java.ext.dirs = /gscloud/server/runtime/java/x86_64-linux/jre/lib/ext:/usr/java/packages/lib/ext
sun.boot.class.path = /gscloud/server/runtime/java/x86_64-linux/jre/lib/resources.jar:/gscloud/server/runtime/java/x86_64-linux/jre/lib/rt.jar:/gscloud/server/runtime/java/x86_64-linux/jre/lib/sunrsasign.jar:/gscloud/server/runtime/java/x86_64-linux/jre/lib/jsse.jar:/gscloud/server/runtime/java/x86_64-linux/jre/lib/jce.jar:/gscloud/server/runtime/java/x86_64-linux/jre/lib/charsets.jar:/gscloud/server/runtime/java/x86_64-linux/jre/lib/jfr.jar:/gscloud/server/runtime/java/x86_64-linux/jre/classes
java.awt.headless = true
java.vendor = AdoptOpenJDK
catalina.base = /tmp/tomcat.5200.6719909097640900997
com.zaxxer.hikari.pool_number = 1
file.separator = /
java.vendor.url.bug = http://bugreport.sun.com/bugreport/
sun.io.unicode.encoding = UnicodeLittle
sun.font.fontmanager = sun.awt.X11FontManager
sun.cpu.endian = little
sun.cpu.isalist =
VM Flags:
Non-default VM flags: -XX:CICompilerCount=3 -XX:InitialHeapSize=528482304 -XX:MaxHeapSize=8434745344 -XX:MaxNewSize=2811232256 -XX:MinHeapDeltaBytes=524288 -XX:NewSize=176160768 -XX:OldSize=352321536 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseParallelGC
Command line: -Dloader.path=./server/runtime/3rd,./server/runtime/libs -Dserver.runtime.path.name=server -Dspring.profiles.active=prod
修改启动配置节
增加启动配置节:
-XX:NativeMemoryTracking=summary
-XX:+UnlockDiagnosticVMOptions
-XX:+PrintNMTStatistics
然后进行验证.
启动成功后查看堆区信息:
jcmd 3153 GC.heap_info
3153:
PSYoungGen total 2737664K, used 839841K [0x0000000718700000, 0x00000007c0000000, 0x00000007c0000000)
eden space 2732032K, 30% used [0x0000000718700000,0x000000074b5a9668,0x00000007bf300000)
from space 5632K, 99% used [0x00000007bfa80000,0x00000007bffff070,0x00000007c0000000)
to space 6656K, 0% used [0x00000007bf300000,0x00000007bf300000,0x00000007bf980000)
ParOldGen total 3923968K, used 3679249K [0x00000005c9400000, 0x00000006b8c00000, 0x0000000718700000)
object space 3923968K, 93% used [0x00000005c9400000,0x00000006a9d044b0,0x00000006b8c00000)
Metaspace used 930784K, capacity 955800K, committed 956056K, reserved 1904640K
class space used 94743K, capacity 100007K, committed 100016K, reserved 1048576K
查看JVM信息- 注意这个是启动成功还未使用时的情况
3153:
Native Memory Tracking:
Total: reserved=11485532KB, committed=8832628KB
- Java Heap (reserved=8237056KB, committed=6669312KB)
(mmap: reserved=8237056KB, committed=6669312KB)
- Class (reserved=1924213KB, committed=975501KB)
(classes #129334)
(malloc=21621KB #196626)
(mmap: reserved=1902592KB, committed=953880KB)
- Thread (reserved=257096KB, committed=257096KB)
(thread #250)
(stack: reserved=255924KB, committed=255924KB)
(malloc=816KB #1253)
(arena=356KB #495)
- Code (reserved=275156KB, committed=144832KB)
(malloc=25556KB #33396)
(mmap: reserved=249600KB, committed=119276KB)
- GC (reserved=309146KB, committed=303022KB)
(malloc=8198KB #3979)
(mmap: reserved=300948KB, committed=294824KB)
- Compiler (reserved=649KB, committed=649KB)
(malloc=518KB #3554)
(arena=131KB #6)
- Internal (reserved=254240KB, committed=254240KB)
(malloc=254208KB #150391)
(mmap: reserved=32KB, committed=32KB)
- Symbol (reserved=186444KB, committed=186444KB)
(malloc=181993KB #2017141)
(arena=4451KB #1)
- Native Memory Tracking (reserved=37718KB, committed=37718KB)
(malloc=90KB #1100)
(tracking overhead=37628KB)
- Arena Chunk (reserved=3815KB, committed=3815KB)
(malloc=3815KB)
通过top的方式进行查看
top -Hp 3153 -bn 1 |head -n 10
top - 17:22:12 up 105 days, 44 min, 6 users, load average: 0.86, 1.33, 1.58
Threads: 250 total, 1 running, 249 sleeping, 0 stopped, 0 zombie
%Cpu(s): 16.7 us, 20.8 sy, 0.0 ni, 61.5 id, 0.0 wa, 0.0 hi, 1.0 si, 0.0 st
KiB Mem : 32946140 total, 4115820 free, 19413000 used, 9417320 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 12976944 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3153 root 20 0 14.4g 8.0g 116096 S 0.0 25.5 0:00.00 java
3154 root 20 0 14.4g 8.0g 116096 S 0.0 25.5 25:46.31 java
3155 root 20 0 14.4g 8.0g 116096 S 0.0 25.5 0:27.38 java
通过pmap查看内存使用情况
pmap -d $pid |tail -n 10
Address Kbytes RSS Dirty Mode Mapping
00007f45727c2000 4 0 0 r---- [ anon ]
00007f45727c3000 4 4 4 rw--- [ anon ]
00007f45727c4000 4 4 4 r---- ld-2.17.so
00007f45727c5000 4 4 4 rw--- ld-2.17.so
00007f45727c6000 4 4 4 rw--- [ anon ]
00007ffddc929000 132 44 44 rw--- [ stack ]
00007ffddc9d4000 8 4 0 r-x-- [ anon ]
ffffffffff600000 4 0 0 r-x-- [ anon ]
---------------- ------- ------- -------
total kB 15106724 8408168 8292060
查看一个运行很多自动化的机器的内存使用情况
SQLSERVER数据库测试环境:
pmap的数值: 23686180
GC.heap_info的数值: 16683520
比率约为: 70%
机器的压力较大. 内存 94%
达梦数据库测试环境:
pmap的数值: 15449264
GC.heap_info的数值: 2005504+6867968
比率约为: 57%
机器的压力较小. 内存 80%
需要注意的是: 第二个是没有设置 Xmx的设置.
第一个设置了XMX还比较好一些.
一个压测环境:
pmap的数值: 21518128
GC.heap_info的数值: 11086848+5490688
比率约为: 77%
机器的压力较小. 内存 50%
这个环境跑的功能不是很多, 所以估计codecache等部分的占用会少一些.
