Thinking Clearly about Performance


performance is not an attribute of a system. performance is an attribute of each individual experience with a system. (percentile specification)

when obviously different experiences yield the same measurement, you're measuring the wrong thing.

skew is what fouls your ability to predict results. # 比如函数A总共花费500s, 一共调用100次。但是其中90次一共花费90s,剩余10次花费410s.

two types of waiting:

tcap-perf.png tcap-qdelay.png tcap-cdelay.png