On Fri, Sep 14, 2012 at 12:40 AM, Nikolay Ulyanitsky <lystor@gmail.com> wrote:
Hi I compiled the 3.6-rc5 kernel with the same config from 3.5.3 and got the 15-20% performance drop of PostgreSQL 9.2 on AMD chipsets (880G, 990X).
Did you compile the AMD code on the AMD system?
We use a different open-source project that provides chemistry functionality, and discovered the hard way that the code optimizer is specific to each chip. Code compiled on Intel chips would sometimes run 50% slower on AMD chips (and vice versa). When we compiled the Intel code using Intel computers and AMD code using AMD computers, the performance difference disappeared.
There's probably an optimizer flag somewhere that would allow you to force it to compile for one chip or the other, but by default it seems to pick the one you're running on.