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进程间通信的一种方式,多个进程共享一段内存,即“共享内存”。与其他的ipc方式(如:pipe,fifo,messages)相比少copy一次内存

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localhost.localdomain kernel: mce: [Hardware Error]: Machine check events logged
localhost.localdomain mcelog[2226]: Hardware event. This is not a software error.
localhost.localdomain mcelog[2226]: MCE 0
localhost.localdomain mcelog[2226]: CPU 0 BANK 7 TSC b98e63765d2
localhost.localdomain mcelog[2226]: MISC 200005c280201086 ADDR 20b5cf8880
localhost.localdomain mcelog[2226]: TIME 1617035952 Tue Mar 30 00:39:12 2021
localhost.localdomain mcelog[2226]: MCG status:
localhost.localdomain mcelog[2226]: MCi status:
localhost.localdomain mcelog[2226]: Corrected error
localhost.localdomain mcelog[2226]: Error enabled
localhost.localdomain mcelog[2226]: MCi_MISC register valid
localhost.localdomain mcelog[2226]: MCi_ADDR register valid
localhost.localdomain mcelog[2226]: MCA: MEMORY CONTROLLER RD_CHANNEL0_ERR
localhost.localdomain mcelog[2226]: Transaction: Memory read error
localhost.localdomain mcelog[2226]: M2M: MscodDataRdErr
localhost.localdomain mcelog[2226]: STATUS 9c00004001010090 MCGSTATUS 0
localhost.localdomain mcelog[2226]: MCGCAP f000c14 APICID 0 SOCKETID 0
localhost.localdomain mcelog[2226]: CPUID Vendor Intel Family 6 Model 85
localhost.localdomain mcelog[2226]: warning: 8 bytes ignored in each record
localhost.localdomain mcelog[2226]: consider an update

内存模块出现错误

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vsyscallvDSO段是用于加速Linux中某些系统调用的两种机制。

The "vDSO" (virtual dynamic shared object) is a small shared library
that the kernel automatically maps into the address space of all user-space applications. Applications usually do not need to concern themselves with these details as the vDSO is most commonly called by the C library. This way you can code in the normal way using standard functions and the C library will take care of using any functionality that is available via the vDSO.

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uptimetop等命令都可以看到load average指标,从左至右三个数字分别表示1分钟5分钟15分钟的load average:

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# uptime
09:52:13 up 20:03, 14 users, load average: 48.59, 46.08, 46.00

判断一个系统负载是否偏高需要计算单核CPU的平均负载,等于这里uptime命令显示的系统平均负载/CPU核数,一般以0.7为比较合适的值, 偏高说明有比较多的进程在等待使用CPU资源。
除了等待运行的进程还有不可中断的线程

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CPU电源状态:C-state(CPU Power states))
CPU性能状态:P-state(CPU Performance states)

The concepts of C/P-states originally come from ACPI (Advanced Configuration and Power Interface) specification, Cx talk about processor sleep status, while P about running status. please check wiki for more details:

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