测试不同的数据结构（最小堆、四叉堆、红黑树、时间轮）实现的定时器的性能差异。

as Hashed and Hierarchical Timing Wheels implies

a timer module has 3 component routines:

// start a timer that will expire after `interval` unit of time
// return an unique id of the pending timer
int Start(interval, expiry_action)

// cancel a timer identified by `timer_id`
void Cancel(timer_id)

// per-tick bookking routine
// in single-thread timer scheduler implementions, this routine will run timeout actions
int Update(now)

use min-heap, quaternary heap( 4-ary heap ), balanced binary search tree( red-black tree ), hashed timing wheel and Hierarchical timing wheel to implement different time scheduler.

FIFO means whether same deadline timers expire in FIFO order.

FIFO的意思是相同到期时间的定时器是否按FIFO的顺序到期

Obtain CMake first.

• sudo apt install cmake on Ubuntu or Debian
• sudo yum install cmake on Redhat or CentOS
• choco install cmake on Windows use choco

run shell command

• mkdir cmake-build; cd cmake-build && cmake -DCMAKE_BUILD_TYPE=Release .. && cmake --build .

Win10 x64 6-core 3.93MHz CPU

• rbtree timer Add/Cancel has not so good performance compare to other implementations;
• 红黑树的插入和删除相比其它实现，表现都弱了一些；
• binary min heap is a good choice, easy to implement and have a good performance, but without FIFO expiration order(heap sort is unstable);
• 最小堆是一个不错的选择，代码实现简单性能也不俗，但不支持相同超时的定时器按FIFO顺序触发;

• Hashed and Hierarchical Timing Wheels
• Hashed and Hierarchical Timing Wheels
• Netty HashedWheelTimer
• Apache Kafka, Purgatory, and Hierarchical Timing Wheels