a: performance expectations
b: higher than performance expectations, system resources are at a critical point
c: higher than expected values, inflection point
d: exceeding the load, the system crashes
In the daily test, point a is based on the performance test target, continuously pressurizing the system to verify that the system is within the acceptable range of resources, and it does not meet the performance target.
a->b: Continue to increase the pressure until one or more performance indicators of the system reach the safety critical value.
b->d: If the safety load is exceeded, continue to pressurize until the bottleneck of the system is determined or user requests cannot be received.