是否可以使用微基准测试框架来计算某些语句？

Question

I am planning to micro benchmark my java code which involves several calls to local as well as remote database. I was about to use System.nanoTime() but started reading about the micro benchmarking frameworks such as jmh and caliper. Use of these frameworks is definitely recommended but from whatever (little) I read, it seems that we can benchmark only a complete method and also it allows us to do this non-invasively (wrt existing code) ie, we need not litter existing code with the code/annotations of jmh/caliper.

I want to benchmark only specific pieces of code (statements) within some methods. Is it possible to do this with any of micro benchmarking frameworks? Please provide some insights into this.

Answer 1

I guess, calls to a DB are usually expensive enough to eliminate most of the problem with microbenchmarking. So your approach was probably fine. If you're measuring it in production, repeating the measurement many times, and don't care about a few nanoseconds, stick with System.nanoTime .

You're doing something very different from microbenchmarking like eg I did here . You're not trying to optimize a tiny piece of code and you don't want to eliminate external influences.

Microbenchmarking a part of a method makes no sense to me, as a method gets optimized as a whole (and possibly also inlined). It's a different level.

I don't think any framework could help, all they can do in your case is automate the work, which you don't seem to need. Note that System.nanoTime may take several hundreds cycles (which is probably fine in your case).

Answer 2

You can try using metrics from codehale . I found its easy to use and low overhead if you are using in certain configuration ie Exponentially decaying Reservoir.

Micro level and precise benchmarking does comes with an associated cost with it ie memory overhead at run time for sampling, benchmark might it self take time for calculation and and stats generation (ideal one would be offsetting that from stats) . But if you want to bench mark db connection which I don't think should be very frequent, metrics might be appropriate, I found its easy to use. and yes it is bit invasive but configurable.