[undertow-dev] Does record-request-start-time really impact performance?

Hi everyone. I'd like to add request duration to our HTTP access log, and found the "record-request-start-time" setting in the documentation. The documentation says "This has a small but measurable performance impact." But is that really true? From what I can see in the code, all it's doing is calling System.nanoTime(). Chasing this led me to a lot of Google searching on nanoTime() itself, and its performance. There's a lot of out-dated information out there, especially with regard to Linux. From what I can see in the Java source, it's using clock_gettime(CLOCK_MONOTONIC), and various sources say this is plenty fast: https://upvoid.com/devblog/2014/05/linux-timers/ (note: this site has an expired certificate as of 2/20, so you'll get a browser complaint) http://stackoverflow.com/questions/38779763/linux-times-or-clock-gettimec... Has anyone measured this at the Undertow level, to see whether "record-request-start-time" really affects performance? -- Matt