标签：sed 最小堆 opp available space 打印 user jstat force
??在linux上跑程序时，常常遇到程序卡顿，内存消耗大，这时候，我们需要使用free查看内存使用情况及top内存消耗排行，当然，我们还可以继续使用一些其他的JVM监控命令如jstat等命令进行java程序的性能评估。
??free命令是显示系统内存的使用情况，一般包括了物理内存、交换内存以及内核缓冲区内存。
[linux@001]$ free --help
Usage:
free [options]
Options:
-b, --bytes show output in bytes
-k, --kilo show output in kilobytes
-m, --mega show output in megabytes
-g, --giga show output in gigabytes
--tera show output in terabytes
-h, --human show human-readable output
--si use powers of 1000 not 1024
-l, --lohi show detailed low and high memory statistics
-t, --total show total for RAM + swap
-s N, --seconds N repeat printing every N seconds
-c N, --count N repeat printing N times, then exit
-w, --wide wide output
--help display this help and exit
-V, --version output version information and exit
[linux@001]$ free -b
total used free shared buff/cache available
Mem: 16657858560 9096298496 5962731520 42442752 1598828544 7198982144
Swap: 0 0 0
[linux@001]$ free -k
total used free shared buff/cache available
Mem: 16267440 8884816 5821264 41448 1561360 7028544
Swap: 0 0 0
[linux@001]$ free -m
total used free shared buff/cache available
Mem: 15886 8757 5612 40 1516 6782
Swap: 0 0 0
[linux@001]$ free -g
total used free shared buff/cache available
Mem: 15 8 5 0 1 6
Swap: 0 0 0
[linux@001]$ free -h
total used free shared buff/cache available
Mem: 15G 8.6G 5.5G 40M 1.5G 6.6G
Swap: 0B 0B 0B
[linux@001]$ free -l -h
total used free shared buff/cache available
Mem: 15G 8.5G 5.6G 40M 1.5G 6.7G
Low: 15G 9G 5.6G
High: 0B 0B 0B
Swap: 0B 0B 0B
[linux@001]$ free -t -h
total used free shared buff/cache available
Mem: 15G 8.5G 5.6G 40M 1.5G 6.7G
Swap: 0B 0B 0B
Total: 15G 8.5G 5.6G
[linux@001]$ free -s 10
total used free shared buff/cache available
Mem: 16267440 8910116 5798884 41448 1558440 7003268
Swap: 0 0 0
total used free shared buff/cache available
Mem: 16267440 8912052 5796892 41448 1558496 7001336
Swap: 0 0 0
Mem：内存的使用情况。Swap：交换空间的使用情况，是磁盘的一块区域，可以是swap分区也可以是swap文件，当系统物理内存使用比较紧张时，Linux会将内存中不常被访问的数据保存到Swap中，若需要访问该内容，会加载到内存中，即换出和换入的意思。total：物理内存总数。used：已使用内存大小。free：可使用内存大小，即未被真正使用过的物理内存大小。shared：多个进程可共享内存大小。buff/cache：磁盘缓存大小。available：可提供的内存大小，区别于free列，如果没有足够的free内存可用，会从buffer/cache回收内存来满足应用程序的需求，所以available=free+buffer+cache。??top命令是用于监控Linux系统状况，可以通过该命令实时查看系统各个进程的资源占用状况。相当于Windows系统的任务管理器。
[linux@001]$ top -help
procps-ng version 3.3.10
Usage:
top -hv | -bcHiOSs -d secs -n max -u|U user -p pid(s) -o field -w [cols]
使用格式：
top [-] [d] [p] [q] [c] [b] [S] [s] [n]
d：指定两次频幕刷新频率，即时间间隔。如top -d 4，指定更新周期为4秒。p：指定监控进程id来监控某个进程状态。如top -p 1201，显示进程号为1201的进程信息、cpu、内存占用等信息。q：无延时刷新，若有超级用户权限，则top会以高优先级运行。c：显示整个命令行。如top -c，显示每个进程的完整命令。S：指定累计模式。如top -S，以累计模式显示程序信息。s：使top命令在安全模式中运行。如top -s，不能交互使用s键位，会报unavailable in secure mode提示。n：指定更新的次数。如top -n 2只更新2次，就退出top程序。b：批处理模式显示程序信息。如top -b，以批处理模式显示程序信息。c键位：切换显示命令名称和完整的命令行。P键位：根据CPU使用百分比大小进行排序。M键位：根据内存mem占有率大小进行排序。n键位：设置在进程列表中显示进程的数量。T键位：根据时间/累计时间进行排序。s键位：改变画面更新频率，输入两次刷新之间的延迟时间，以秒为单位。S键位：切换到累计模式；开关。i键位：忽略闲置和僵尸进程；开关。h键位：显示帮助画面。u键位：输入指定的user，就会显示所有该user的程序进程。q键位：退出top查看程序。f键位：编排视图显示字段。
top - 09:48:58 up 27 days, 23:42, 6 users, load average: 0.10, 0.27, 0.37
Tasks: 163 total, 1 running, 160 sleeping, 2 stopped, 0 zombie
%Cpu(s): 0.6 us, 1.2 sy, 0.0 ni, 98.1 id, 0.1 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 16267440 total, 6819976 free, 8980392 used, 467072 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 6944052 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
1926 root 20 0 1020672 3584 0 S 0.3 0.0 71:41.44 vmsec-linux
2501 bdoc 20 0 8421520 569828 3876 S 0.3 3.5 26:53.14 java
7899 root 20 0 148656 6044 4368 S 0.3 0.0 0:13.34 sshd
12912 root 20 0 0 0 0 S 0.3 0.0 3:03.64 kworker/0:2
31032 root 20 0 0 0 0 S 0.3 0.0 0:43.88 kworker/4:2
1 root 20 0 191196 3132 1428 S 0.0 0.0 0:33.66 systemd
2 root 20 0 0 0 0 S 0.0 0.0 0:00.38 kthreadd
3 root 20 0 0 0 0 S 0.0 0.0 0:04.44 ksoftirqd/0
5 root 0 -20 0 0 0 S 0.0 0.0 0:00.00 kworker/0:0H
7 root rt 0 0 0 0 S 0.0 0.0 0:43.99 migration/0
若按下1数字键，进行多核展示
top - 10:35:29 up 28 days, 29 min, 6 users, load average: 0.09, 0.15, 0.25
Tasks: 159 total, 1 running, 156 sleeping, 2 stopped, 0 zombie
%Cpu0 : 1.3 us, 1.3 sy, 0.0 ni, 97.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu1 : 0.7 us, 1.3 sy, 0.0 ni, 98.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu2 : 1.0 us, 1.0 sy, 0.0 ni, 98.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu3 : 0.7 us, 1.3 sy, 0.0 ni, 98.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu4 : 0.7 us, 0.7 sy, 0.0 ni, 98.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu5 : 0.7 us, 1.0 sy, 0.0 ni, 96.0 id, 2.3 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu6 : 1.0 us, 1.7 sy, 0.0 ni, 97.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu7 : 1.0 us, 1.0 sy, 0.0 ni, 98.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 16267440 total, 6706632 free, 8955152 used, 605656 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 6968016 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
7899 root 20 0 148656 6048 4368 S 0.7 0.0 0:24.99 sshd
1926 root 20 0 1020672 3584 0 S 0.3 0.0 71:46.39 vmsec-linux
2726 mysql 20 0 4795092 849484 4984 S 0.3 5.2 1835:23 mysqld
4363 bdoc 20 0 8445056 1.898g 14052 S 0.3 12.2 1:53.14 java
8185 bdoc 20 0 10.126g 1.471g 12908 S 0.3 9.5 35:39.03 java
8520 root 20 0 158684 3028 1568 S 0.3 0.0 0:14.86 top
25718 bdoc 20 0 157708 2248 1568 R 0.3 0.0 0:00.17 top
统计信息区的前5行是系统整体的系统信息。
1）第1行是任务队列信息，这个类似于uptime命令的执行结果：
[linux@001]$ uptime
09:50:06 up 27 days, 23:43, 6 users, load average: 1.13, 0.47, 0.43
2）第2、3行是进程和cpu的统计信息。
tasks：进程任务数：
total：表示进程总数；running：表示正在运行的进程数；sleeping：表示睡眠的进程数；stopped：表示停止的进程数；zombie：表示僵尸进程数；%Cpu(s)：cpu使用情况，多核展示也可以通过按1数字，就会变成%Cpu0，%Cpu1，%Cpu2... ...
us：user，time running un-niced user processes 用户空间占用cpu百分比；sy：system，time running kernel processes 内核空间占用cpu百分比；ni： nice ， time running niced user processes 用户进程空间内改变过优先级的进程占用cpu百分比；id：idle， time idel processes 空闲cpu百分比；wa：IO-wait ，time waiting for I/O completion 等待输入输出cpu时间百分比；hi：hardware interrupts，time spent servicing hardware interrupts 硬件cpu中断占用百分比；si：software interrupts，time spent servicing software interrupts 软中断占用百分比；st：time stolen from this vm by the hypervisor虚拟机占用百分比；cat /proc/cpuinfo查看cpu信息：
Mem：物理内存total：物理内存总量。free：物理空闲内存量。used：物理已使用内存量。buff/cache：物理内核缓存内存量。Swap：交换区total：交换区总量。free：交换区空闲量。used：交换区使用量。avail Mem：交换区可用量。4）第7行是各进程的监控
PID：进程id。USER：进程所有者。PR：进程优先级。NI：nice值，负值表示高优先级，正值表示低优先级。VIRT：进程使用的虚拟内存总量，单位是kb，VIRT=SWAP+RES。RES：进程使用的、未被换出的物理内存大小，单位kb，RES=CODE+DATA。SHR：共享内存大小，单位kb。S：进程状态。D：不可终端的睡眠状态；R：运行状态；S：睡眠状态；T：跟踪/停止状态；Z：僵尸进程状态。%CPU：上次更新到现在的CPU时间占用百分比。%MEM：进程使用的物理内存百分比。TIME+：进程使用的CPU时间总长，单位1/100秒。COMMAND：进程命令名称/命令行。??首先得明确一下JVM中的堆内存的概念，堆内存=年轻代+年老代+永久代+元数据，而年轻代=Eden区+两个Survivor区（From及To）
??一般常用jstat -gc PID查看某个进程的堆内存使用情况。
使用语法格式
jstat -<option> [-t] [-h<lines>] <vmid> [<interval> [<count>]]
参数解释：
用的比较多的是：jstat -gc PID和jstat -gcutil PID
Option Displays...
-class: Statistics on the behavior of the class loader.-compiler: Statistics of the behavior of the HotSpot Just-in-Time compiler.-gc: Statistics of the behavior of the garbage collected heap.-gccapacity: Statistics of the capacities of the generations and their corresponding spaces.-gccause: Summary of garbage collection statistics (same as -gcutil), with the cause of the last and current (if applicable) garbage collection events.-gcnew: Statistics of the behavior of the new generation.-gcnewcapacity: Statistics of the sizes of the new generations and its corresponding spaces.-gcold: Statistics of the behavior of the old and permanent generations.-gcoldcapacity: Statistics of the sizes of the old generation.-gcpermcapacity: Statistics of the sizes of the permanent generation.-gcutil: Summary of garbage collection statistics.
Column Description
S0C： Current survivor space 0 capacity (KB).S1C： Current survivor space 1 capacity (KB).S0U： Survivor space 0 utilization (KB).S1U： Survivor space 1 utilization (KB).EC: Current eden space capacity (KB).EU： Eden space utilization (KB).OC： Current old space capacity (KB).OU： Old space utilization (KB).PC： Current permanent space capacity (KB).PU： Permanent space utilization (KB).YGC： Number of young generation GC Events.YGCT： Young generation garbage collection time.FGC： Number of full GC events.常用FGCT： Full garbage collection time. 常用GCT： Total garbage collection time.常用??jmap命令可以用于对堆进行立项分析，检查对象创建、数量及对象所占内存大小。一般使用jmap -heap PID用于打印堆使用情况。
jmap [ option ] pid：连接进程号
jmap [ option ] executable core：连接核心文件
jmap [ option ] [server-id@]remote-hostname-or-IP：连接远程debug服务的主机名或ip
[linux@001]$ jmap -h
Usage:
jmap [option] <pid>
(to connect to running process)
jmap [option] <executable <core>
(to connect to a core file)
jmap [option] [server_id@]<remote server IP or hostname>
(to connect to remote debug server)
where <option> is one of:
<none> to print same info as Solaris pmap
-heap to print java heap summary
-histo[:live] to print histogram of java object heap; if the "live"
suboption is specified, only count live objects
-clstats to print class loader statistics
-finalizerinfo to print information on objects awaiting finalization
-dump:<dump-options> to dump java heap in hprof binary format
dump-options:
live dump only live objects; if not specified,
all objects in the heap are dumped.
format=b binary format
file=<file> dump heap to <file>
Example: jmap -dump:live,format=b,file=heap.bin <pid>
-F force. Use with -dump:<dump-options> <pid> or -histo
to force a heap dump or histogram when <pid> does not
respond. The "live" suboption is not supported
in this mode.
-h | -help to print this help message
-J<flag> to pass <flag> directly to the runtime system
[linux@001]$ netstat -npl | grep 8889
(Not all processes could be identified, non-owned process info
will not be shown, you would have to be root to see it all.)
tcp6 0 0 :::8889 :::* LISTEN 7253/java
[linux@001]$ jmap -heap 7253
Attaching to process ID 7253, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 25.65-b01
using thread-local object allocation.
Parallel GC with 8 thread(s)
Heap Configuration: #堆配置，即JVM参数配置
MinHeapFreeRatio = 0 #最小堆使用比例
MaxHeapFreeRatio = 100 #最大堆使用比例
MaxHeapSize = 4164943872 (3972.0MB) #最大堆空间大小
NewSize = 87031808 (83.0MB) #新生代分配大小
MaxNewSize = 1388314624 (1324.0MB) #最大新生代可分配大小
OldSize = 175112192 (167.0MB) #老年代大小
NewRatio = 2 #新生代比例
SurvivorRatio = 8 #新生代和survivor比例
MetaspaceSize = 21807104 (20.796875MB) #元数据空间大小
CompressedClassSpaceSize = 1073741824 (1024.0MB) #指针空间大小
MaxMetaspaceSize = 17592186044415 MB #MaxMetaspaceSize=Compressed Class Space Size + Metaspace area (excluding the Compressed Class Space) Size
G1HeapRegionSize = 0 (0.0MB) #G1中的region大小
Heap Usage:
PS Young Generation
Eden Space: #eden区
capacity = 1342177280 (1280.0MB)
used = 970477176 (925.519157409668MB)
free = 371700104 (354.48084259033203MB)
72.30618417263031% used
From Space: #from区，即survivor1区
capacity = 23068672 (22.0MB)
used = 22904896 (21.84381103515625MB)
free = 163776 (0.15618896484375MB)
99.29005015980114% used
To Space: #to区，即survivor2区
capacity = 23068672 (22.0MB)
used = 0 (0.0MB)
free = 23068672 (22.0MB)
0.0% used
PS Old Generation #老年代使用情况
capacity = 176685056 (168.5MB)
used = 52151696 (49.73573303222656MB)
free = 124533360 (118.76426696777344MB)
29.5167555087398% used
31742 interned Strings occupying 3385416 bytes.
ps -eLf | grep java | wc -l
ps -ef | grep PID
netstat -n | grep tcp | grep 程序端口号| wc -l
pmap PID
top -Hp PID
标签：sed 最小堆 opp available space 打印 user jstat force
原文地址：https://www.cnblogs.com/Andya/p/12967853.html
