On Tue, May 7, 2019 at 10:06 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Given the described test setup, I'd put basically no stock in these
> numbers. It's unlikely that this test case's performance is CPU-bound
> per se; more likely, I/O and lock contention are dominant factors.
> So I'm afraid whatever they're measuring is a more-or-less chance
> effect rather than a real system-wide code improvement.
Or a compiler bug. Link-time optimizations give the compiler a view of
the program as a whole, not just a single TU at a time. This enables
it to perform additional aggressive optimization.
--
Peter Geoghegan