Re: __atomic_test_and_set() and mips o32 - help wanted

[Jason Thorpe <thorpej%me.com@localhost>]

> On Nov 19, 2025, at 10:53 AM, Maciej W. Rozycki <macro%orcam.me.uk@localhost> wrote:
> 
> Nothing wrong with it in principle, especially if you do want to optimise 
> for MIPS I.  Traps are cheap on MIPS however, and even more so with MIPS I 
> and its simple four-stage execution pipeline, so it might be the case of 
> perfect being the enemy of good enough.  There is a balance to be found 
> here.

The traps themselves are cheap, but that does not always equate to “trap handling is cheap”.

I agree with you vis a vis "making appropriate trade-offs is good, actually”, but I’d also like to point out that work described in the original paper on restartable atomic sequences was done on an R3000 (DECstation 5000/200).

-- thorpej