timers-bench

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This project measures timer latency (average time spent on timer call) and granularity (average time in for which timer value stays the same) of System.nanoTime() and System.currentTimeMillis() in a few modes. This gives the estimates on the timer precision used for performance assessment. I could do this experiment internally, but figured other guys would find this data useful as well.

Build it from source: $ mvn clean package

Run it: $ java -jar target/timerbench.jar

Sample output:

---- 8< (cut here) ----------------------------------------- Java(TM) SE Runtime Environment, 1.8.0-b132 Java HotSpot(TM) 64-Bit Server VM, 25.0-b70 Linux, 3.13.0-custom+, amd64

Burning up to figure out the exact CPU count....... done!

Running with 1 threads and [-client]: granularity_currentTime: 989264.177 +- 1769.248 ns granularity_nanotime: 35.077 +- 0.131 ns latency_currentTime: 42.370 +- 2.374 ns latency_nanotime: 35.430 +- 0.107 ns

Running with 2 threads and [-client]: granularity_currentTime: 993246.791 +- 1523.273 ns granularity_nanotime: 49.965 +- 3.673 ns latency_currentTime: 51.368 +- 3.529 ns latency_nanotime: 42.261 +- 4.616 ns

Running with 4 threads and [-client]: granularity_currentTime: 1005131.127 +- 6633.599 ns granularity_nanotime: 56.744 +- 2.014 ns latency_currentTime: 59.416 +- 2.466 ns latency_nanotime: 54.162 +- 1.247 ns

Running with 1 threads and [-server]: granularity_currentTime: 989051.057 +- 1759.073 ns granularity_nanotime: 35.422 +- 0.488 ns latency_currentTime: 40.839 +- 0.103 ns latency_nanotime: 35.457 +- 0.340 ns

Running with 2 threads and [-server]: granularity_currentTime: 993251.781 +- 899.136 ns granularity_nanotime: 45.761 +- 4.810 ns latency_currentTime: 48.669 +- 4.069 ns latency_nanotime: 40.424 +- 4.293 ns

Running with 4 threads and [-server]: granularity_currentTime: 1000651.038 +- 4507.238 ns granularity_nanotime: 55.954 +- 1.864 ns latency_currentTime: 59.752 +- 1.937 ns latency_nanotime: 54.484 +- 4.416 ns

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