the test system has always been our development, testing, maintenance. Recently, we have been observing exams, each time hundreds of students log in simultaneously, the server CPU and memory, the database log display data becomes particularly important.
Here is the server memory for a certain time period.
First,CPU and memory phenomena during exams:
The students began to draw questions, when the test, the CPU share from almost 0 of the place began to rise, memory share from about 4 G began to rise. After about thirty or forty seconds, the CPU can reach up to 70% or so, and the memory can reach more than 6 grams. After 1 minutes, the CPU and memory occupy begin to drop, eventually reaching cpu15%, memory 4. 3 G or so.
second, CPU use
Why do we have to stare at the ups and downs of CPU usage? This data represents the currently occupied resources of the CPU. If the CPU is too high for a long time, there are several reasons:
1. The virus in the computer.
For example: encountered ARP virus, resulting in the entire test system paralysis.
2. Software or code has errors
For example: The picture in the code is not read from MongoDB, the CPU will appear a peak, each error will appear a peak value.
3. Need to upgrade your computer
iii. use of PF
PF (pagefile) virtual memory. When the physical memory is not enough, the temporary unused data is temporarily put into the virtual memory of the hard disk, the best way to reduce PF is to increase the memory.
Reasons for PF Increase:
1. Physical memory is too small
2. Startup program is too large
3. Virtual memory settings are unreasonable
To modify virtual memory:
My Computer--Properties--advanced--performance--Settings--advanced--Virtual memory--settings--Change--Select the partition where the virtual memory is placed (recommended partition outside the system disk)--Choose the size of custom or system management--settings--Determine
Also on the Internet to check the corresponding 4 frame inside the meaning of the noun.
Iv. Summary
The problem is usually at the beginning, the examination system is no exception. Look at the system on-line, to understand how their predecessors to find problems, solve problems, but also a great harvest. CPU, memory parsing first write to this, the following article is about the test system of SQL database optimization problem, I hope to provide you with some ideas.
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Windows Task Manager CPU usage and PF parsing--"exam system"