System load under CentOS

The loadaverage in The uptime Command echo is similar to the w command, indicating the average number of processes in the process queue in the past 1 minute, 5 minutes, and 15 minutes. Note that the value of loadaverage is the output value. The size of these three values cannot be greater than the number of logical CPUs of the system. for example, the output system has four logical CPUs, if the load average in the lo uptime command Echo is similar to the w command, it indicates the average number of processes in the process queue in the past 1 minute, 5 minutes, and 15 minutes. Note that the output value of load average is generally not larger than the number of logical CPUs of the system. for example, the system has four logical CPUs in the current output, if the three load average values are greater than 4 for a long time, the CPU is busy and the load is high, which may affect the system performance, generally, the system performance is not affected. On the contrary, if the output value of load average is smaller than the number of CPUs, it indicates that the CPU is still idle. for example, the output in this example, the CPU is relatively idle. When the CPU is completely idle, the average load is 0. when the CPU workload is saturated, the average load is 1. the system load is 0, which means there is no vehicle on the bridge. the system load is 0.5, it means there is a car in half of the bridge section. the system load is 1.0, which means there is a car in all sections of the bridge, that is, the bridge is "full. However, it must be noted that the bridge can still pass smoothly until now. the system load is 1.7, which means there are too many vehicles and the bridge is full (100% ), the vehicles waiting for the bridge are 70% of the bridge deck vehicles. Similarly, the system load of 2.0 means that the number of vehicles waiting for the bridge is the same as that of the bridge deck. the system load of 3.0 means that the number of vehicles waiting for the bridge is twice that of the bridge deck. In short, when the system load is greater than 1, the rear of the vehicle must wait; the larger the system load, the longer the bridge must wait. The system load of the CPU is basically the same as the above analogy. The traffic capacity of the bridge is the maximum workload of the CPU; the vehicles on the bridge are processes waiting for CPU processing ). If the CPU processes a maximum of 100 processes per minute, the system load is 0.2, which means that the CPU only processes 20 processes in this minute; the system load is 1.0, this means that the CPU handles 100 processes in the past minute. the system load is 1.7, which means that in addition to the 100 processes that the CPU is processing, 70 processes are waiting in queue for CPU processing. When the system load continues to exceed 0.7, you must begin to investigate where the problem is, to prevent the situation from deteriorating. When the system load continues to exceed 1.0, you must find a solution to reduce this value. When the system load reaches 5.0, it indicates that your system has a very serious problem, does not respond for a long time, or is close to the dead. You should not allow the system to reach this value. Therefore, two CPUs indicate that the system load can reach 2.0, and each CPU has a workload of 100%. To promote it, computers with n CPUs have an acceptable system load of up to n.0. Run the "cat/proc/cpuinfo" command to view CPU information. The "grep-c 'model name'/proc/cpuinfo" command directly returns the total number of CPU cores. If only one minute's system load is greater than 1.0, and the other two time periods are less than 1.0, this indicates that it is only a temporary phenomenon and the problem is not serious. If the average system load exceeds 1.0 within 15 minutes (after the number of CPU cores is adjusted), the problem persists. Therefore, you should mainly observe the "15-minute system load" and use it as an indicator for normal computer operation.