3 ms·

> The "1st cup of coffee" always takes the same amount of time in CPU-land. The 2nd-cup of coffee was speculatively made, but never "slowed down the first cup o

• dragontamer 7y ago
  > Just to be clear, then: the analogy from the original post doesn't apply. The analogy from the original post applies to the cases the original post discusses. The original "coffee latency" blogpost innately applies to a 1980s style computer: a simple in-order machine. Its truly correct for that model of simple computing. I've added in complications: pipelining, superscalar, and speculative execution, which were inventions deployed in the early 90s and 00s to CPUs. So things work differently on modern machines, because modern machines have many, many more features than the "original" computer designs. The original "cups of coffee" are a good way to start thinking about latency vs bandwidth problem. I really like the analogy. But it would take a LOT more writing before I really cover everything going on in modern CPUs.
  • fiter 7y ago
    Your original post was missing explanation because you referenced the original analogy without addressing how the original analogy no longer applied to the scenario you were discussing. For what it's worth, in all my replies I have not been confused about the behavior of a CPU, but only about how you are trying to use the analogy to fit your exposition.