System throughput (TPS), user concurrency

PS: The following are the main concepts and calculation formulas for performance testing, which are documented below:

A System Swallow metric elements:

The Swallow metric (pressure capability) of a system is closely associated with the request for CPU consumption, external interfaces, Io, and so on.

The higher the CPU consumption of a single reqeust, the slower the external system interface and IO effect, the lower the system throughput capacity, and the higher the reverse.

Several important parameters of system throughput: QPS (TPS), concurrency, response time

QPS (TPS): number of request/transactions per second

Concurrent Number: the number of request/transactions that the system processes concurrently

response Time: Average response time is generally taken

(a lot of people often confuse concurrency with TPS understanding)

Once you understand the meaning of the above three elements, you can deduce the relationship between them:

QPS (TPS) = concurrency number/average response time

A system throughput is usually determined by the QPS (TPS), the number of concurrent two factors, each system these two values have a relative limit value, under the application scenario access pressure, as long as a certain item reached the highest system value, the system throughput will not go up, if the pressure continues to increase, the system throughput will decline, The reason is that the system is overloaded, and other consumption such as context switching, memory, and so on is causing system performance degradation.

Determining system Response Time elements

We do the project to schedule, can more than one concurrent multi-task, can also be a person or many people serial work, there will always be a critical path, this path is the project duration.

The response time of a system call is the same as the project plan, and there is a critical path, which is the system impact time;

The critical path consists of CPU operation, IO, External system response and so on.

System throughput (TPS), user concurrency