DDL Resource Control

[hawkingrei]

DDL Resource Control foundmental lib build

We will support three features about them， they are the basic interface to get resource states of container(CPU, Memory etc). Also it will be use by other feature as an foundmental capacity of TiDB kernel.

VPA

• support vertical pod autoscaler #37707

Dynamic Goroutine Pool

• Dynamic Gorotinue Pool #38039

Resource mange

• add rfc to resource manage #41184
• add resource manage to schedule pool by static #39657
• resource manager scheduler goroutine pool #40412

GOGC tuner

• Import Semi-Automated GOGC Tuning To Avoid GC Frequently #32090
• add variable to dynamically change the threshold of GOGC tuner #38431
• make GOGC tuner to support the VPA #38272

Other

• manage runtime.ReadMemStats to avoid stop-the-world too much #38271
• math: add exponential moving average #39488
• add GetCPUUsage #39614
• add metrics for EMA CPU usage #40029