itsmydamnation (no.delete@this.way.com) on September 18, 2020 3:19 pm wrote:
> Andrei F (andrei.delete@this.anandtech.com) on September 18, 2020 3:26 am wrote:
> > Because the OS is irrelevant. There's no system calls in either
> > SPEC or GeekBench, you're just running binary code on the CPU.
> >
> > The only valid concern is compiler differences between Apple's Xcode LLVM toolchain vs the
> > public Clang toolchains, and I've been told by industry people the differences are minor.
>
> Why are there still large differences been Linux and Windows in GB5?

I've found OS to definitely be relevant, from ABI differences, to task scheduling and frequency governors, and even where code/data is placed in binaries/memory (e.g. affecting cache conflicts due to associativity/banking etc - perhaps not strictly an OS thing, but it can have an effect nonetheless).

Differences probably aren't significant most of the time, but I've noted them in repeatable tests on mostly pure CPU code.