Understanding of performance test indicators--CPU and load

For the first time to do performance testing, according to the operation of the document bumps completed, and got the results, see a bunch of indicators and data, or dumbfounded, do not know what the indicators are meant.

Consulted Daniel and degrees Niang, digestion understand a bit, do not know is not correct.

CPU Usage Rate:

CPU usage over a period of time, from this indicator can be seen in a certain period of time the CPU resources are occupied.

Load Average :

The sum of the number of processes that the CPU is processing and waiting for the CPU to process over a certain period of time. Load average is the state of CPU usage from another angle.

The relationship between CPU usage and load average:

Take a hospital checkup to do an example:

User: Students to be examined

CPU: Inspection of the Department (b ultrasound, ophthalmology .... ）

1, Load high, low CPU utilization:

Ophthalmology a total of 3 doctors, check the order, must be the previous doctor to check the end before the next doctor to deal with

Because the first doctor's examination took a long time, resulting in a lot of students in the queue, but the next 2 doctors are in a free state.

Load: Waiting classmate, due to waiting for more classmates, so load value is higher

CPU usage: Only one doctor is working, so CPU utilization is 33.33%

2, load low, high CPU utilization:

Suppose there are as many doctors in the B-Ultrasound department as the eye, but each doctor's work is independent.

The time to come to a new classmate is about checking out a classmate.

Load: Waiting for the classmate, basic <=1

CPU usage: Every doctor is busy, CPU usage is close to 100%

From the above can be seen, not simply from one aspect of the performance of the pros and cons. Similarly, performance tuning can be started in many ways.

Understanding of performance test indicators--CPU and load