I have stumbled on an impossibly good performance behaviour with PostSharp. To evaluate the speed I wrote a little program, that would execute one function a specified number of times, and if PostSharp is enable it would generate and delete a few hundred strings, just in memory (non fixed composition, so they are not auto-interned). The loop executes in a non-trivial (a few milliseconds) amount of time.
Now, I am unable to measure the difference on a few million runs, and a crazy run of ~40 billion iterations amounted to a difference of just a few nanoseconds vs non-PostSharp version doing the same number of calls. To me, this is impossible. There must be something wrong with my test. I had the code peer-reviewed by my co-workers, so I am fairly confident the code does what I intend it to.
So, is there something wrong with using string generation (which is the expected use in the intended applications) as the slow-running simulation for the benchmarks?
Alternatively, has someone else performed (or know of) a PostSharp’s runtime performance analysis?
Thank you.
On a 3 GHz processor, 40 billion clock cycles alone will take 13 seconds – and I sincerely doubt that a single iteration is taking just one clock cycle. Something’s definitely wrong with your test.
Something’s likely getting optimized away – maybe it sees that you’re doing the same thing over and over again and is deciding not to do it at all (except the first time). You need to make sure you’re randomizing your data when you do perf analysis.