condition variable 是啥？ condition variable 是啥？本质上就是一个状态变量 +队列。现实世界中，想要进行下一步的行动，往往需要满足一定的条件(condition)。如十字路口

a association a connection or cooperative link between people or organizations allot to assign as a share or portion ad-hoc An ad hoc activity or organization is done or formed only because a situation has made it necessary and is not planned in advance.Ad hoc is a word that originally comes from Latin and means “for this” or "for this situation." In current

为啥需要 lock？ 多处理器的存在 中断的存在 lock 是啥？ lock 本质上是一个变量。变量本质上是一块内存。归根结底，lock 就是一块内存，用这块内存来保证

There can be many caches stacked on top of each other. Cache 可以一层一层累积。 if you miss in one you try in the “lower level cache” Lower level, mean higher number. 在上层的 Cache miss 了，可以在下层的 Cache 去找。依次类推

TCP 要解决的问题 references tcp-congestion-control tcp-congestion-control-ppt