@cstross I worked with a library from a company that had incredibly bad performance on the Mac compared to PC and we pushed back on that a lot. Nothing happened. Finally, they sent me over to consult with their Mac engineer and when browsing through the code, I saw #define MAC_SLOW_ALLOC 1 or some such thing. I asked what that did and it did all kinds of sanity checking and debug things and it was turned on in release. I asked why that was and he said, "huh. That shouldn't happen" and set it to 0. Face meet palm. Performance improved dramatically. The management was thrilled and bought a sheet cake to celebrate. I told some of the senior engineers there what happened. They fired him a week later. A month after that, I was seeing fragmentation issues because their actual allocator was not very good, so I rewrote it for them as a gift.