I have a background Ruby/Rails job that does a) download resources from some web site; b) massage the data; c) save data to file system. The task is I/O bound and I want to be able to monitor the I/O performances and latency. I hook it up according to New Relic doc and set up measured methods using Method Tracer. However, apparently, NR only reports the CPU times instead of I/O (or real clock time) since the numbers match with the CPU time reported by the Benchmark library. (In fact, the NR documentation does not seem to mention exactly what it is reporting -- user, cpu or clock times.) How do I get NR to report I/O (or at least clock time) of parts of my codes. (Notice I'm not interested in the Disk I/O utilization report NR provides, as the performance problem is due to I/O latency.) Thanks
Figured out by testing with a 'sleep(1)' added to step (c). This force the step to be artificially expensive and it shows up correctly in the NR details. NR does record real clock time (using Time.now) instead of cpu/sys times.