It;s funny you mentioned Marc worked on latency viz and used it to tell a story.
Dick Lyon at Google did the same thing for Google's storage servers https://www.pdl.cmu.edu/SDI/2015/slides/DatacenterComputers.... (starting at Slide 62) identifying various queues and resource contention as major bottlenecks for block storage.
A picture can be worth way more than a thousand words, but sometimes you have to iterate through a thousand pictures to find the one that tells the right story, or helps you ask the right question!
