Re: [PATCH v4] Avoid manual shift-and-test logic in AllocSetFreeIndex

Greg Stark <gsstark@mit.edu> writes:
> I also wonder if this microbenchmark is actually ok because it's
> testing the same value over and over so any branch-prediction will
> shine unrealistically well.

Yeah, that is a good point --- and it would benefit the unrolled loop
more than the other versions.  We should probably revise the test
harness so it mixes the size requests a bit.  I'm not sure of a suitably
simple way to do that, though.
        regards, tom lane