On Tue, 15 Nov 2022, Jonathan Wakely wrote:
> > How about the following:
> >
> > When emitting a compare-and-swap loop for @ref{__sync Builtins}
> > and @ref{__atomic Builtins} lacking a native instruction, optimize
> > for the highly contended case by issuing an atomic load before the
> > @code{CMPXCHG} instruction, and invoke the @code{PAUSE} instruction
> > when restarting the loop.
>
> That's much better, thanks. My only remaining quibble would be that
> "invoking" an instruction seems only marginally better than running
> one. Emitting? Issuing? Using? Adding?
Right, it should be 'using'; let me also add 'to save CPU power':
When emitting a compare-and-swap loop for @ref{__sync Builtins}
and @ref{__atomic Builtins} lacking a native instruction, optimize
for the highly contended case by issuing an atomic load before the
@code{CMPXCHG} instruction, and using the @code{PAUSE} instruction
to save CPU power when restarting the loop.
Alexander
