One: CPU
1. The user-state CPU is the percentage of the total CPU time that executes the application code.
The system-State CPU is the percentage of the total CPU time that the application performs operating system calls. System-State CPU high means that shared resources are competing or there is a lot of interaction between I/O devices.
One goal of improving application performance and scalability is to minimize system-state CPU usage.
2. The CPU run queue is a lightweight process that is ready to run and waiting for available CPUs.
When the running queue length reaches 4 of the processor or more, the corresponding system is very slow.
There are two ways to resolve the run queue Length:
1). Increase the CPU to share the load;
2). Analyze the application running in the system, improve the CPU utilization;
1. Vmstat
procs-----------Memory-------------Swap-------io-----system--------CPU-----r B swpd free buff cache si so bi bo in CS US sy ID WA St 2 0 0 104956 868 825812 0 0 1 5 0 0 0 0
R:cpu Run Queue Length, value is the actual number of lightweight processes in the running queue
US: User-State CPU utilization
SY: System State CPU usage
ID:CPU Idle Rate
2. Top
top-09:42:04 up 3 days, 3 min, 1 user, load average:0.00, 0.01, 0.05tasks:108 Total, 3 running, sleeping, 0 Stopped, 0 zombie%cpu (s): 0.0 us, 0.0 sy, 0.0 ni,100.0 ID, 0.0 wa, 0.0 hi, 0.0 si, 0.0 stkib mem:1015472 Total , 104568 free, 84224 used, 826680 Buff/cachekib swap:0 Total, 0 free, 0 used. 727760 avail Mem PID USER PR NI VIRT RES SHR S%cpu%MEM time+ COMMAND 784 root 0 553064 16340 5748 S 0.0 1.6 0:21 . tuned 743 Root 20 0 110512 13140 676 S 0.0 1.3 0:00.13 dhclient 9678 polkitd 0 527456 13128 4680 S 0.0 1.3 0:00.09 POLKITD 1 root 0 43684 6176 3804 S 0.0 0.6 0:05.08 systemd
The upper part is the statistical information of the whole system, and the lower half is the statistics of the process.
Two: Memory
1. When the system is using paging or virtual memory, there is a memory replacement when accessing memory in swap and the JVM garbage collection in swap, there is definitely a problem with performance;
2.
The authoritative guide to Java Performance Optimization-reading notes (i)-operating System performance monitoring tool