典型PC系统各操作指令执行时间
典型PC系统各种操作指令的大概时间
execute typical instruction
执行基本指令
1/1,000,000,000 sec = 1 nanosec
fetch from L1 cache memory
从一级缓存中读取数据
0.5 nanosec
branch misprediction
分支误预测
5 nanosec
fetch from L2 cache memory
从二级缓存获取数据
7 nanosec
Mutex lock/unlock
互斥加锁/解锁
25 nanosec
fetch from main memory
从主内存获取数据
100 nanosec
send 2K bytes over 1Gbps network
通过1G bps 的网络发送2K字节
20,000 nanosec
read 1MB sequentially from memory
从内存中顺序读取1MB数据
250,000 nanosec
fetch from new disk location (seek)
从新的磁盘位置获取数据(随机读取)
8,000,000 nanosec
read 1MB sequentially from disk
从磁盘中顺序读取1MB数据
20,000,000 nanosec
send packet US to Europe and back
从美国发送一个报文包到欧洲再返回
150 milliseconds = 150,000,000 nanosec