Steven Winfield <Steven.Winfield@xxxxxxxxxxxxxxxxx> writes: > A few days ago a blog post appeared on phoronix.com[1] comparing GCC 8.3.0 against 9.0.1 on Intel cascadelake processors. > A notable difference was seen in the PostgreSQL benchmark (v10.3, pgbench, read/write, more detail below), both when compiling with -march=native and -march=skylake: > I'm interested to know the devs' take on this is - does GCC 9 contain some new feature(s) that are particularly well suited to compiling and optimising Postgres? Or was GCC 8 particularly bad? 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. It is an interesting report, all the same. regards, tom lane
