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SubjectRe: Assignment of GDT entries
Linus Torvalds wrote:
> So I'd not be surprised if movign the TLS segments around would break
> something.
>

I don't think so. 32-bit code running on x86-64 has different TLS
selectors, and everything seems to work there...

> That said, numbers talk, bullshit walks. If the above just works a lot
> better for all modern CPU's that all have 64-byte cachelines (because now
> _everything_ is in that bigger cacheline), and if you can show that with
> numbers, and nothing breaks in practice, then hey..
>

My goal would be to do a minimal change which packs all the useful stuff
together in a 64-byte line. Ideally it would just use two 32-byte
lines, but I don't think that's as important.

Caching effects are pretty hard to measure anyway, and with something as
deeply x86-microarchitectural as this, I could imagine lots of other CPU
cleverness which could obscure any simple measurement. But packing
things into a line certainly can't hurt.

I'll put something together, and see how it goes...

J
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