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Re: tr1::shared_ptr and v3's atomic ops
On Thu, Mar 24, 2005 at 10:31:59AM -0800, Richard Henderson wrote:
> [*] Well, those that can perform them at all without resorting to
> spinlocks. So true 80386 is out for many of them, as is Sparc prior
> to v9. I'm sure there are other small architectures that just can't
> hack it either.
I haven't studied the ia64 atomicity design, but it seems to me we
would best distinguish atomicity guarantees on systems with multiple
processors from that on just a single processor. This translates
to bus-transaction vs. instruction-interrupt atomicity. For 386 and
similarly obscure targets, instruction-interrupt atomicity probably
suffices, and is far better than falling back to mutex (never mind
spinlock!), which probably is, itself, just as fraught on those
targets.
Nathan Myers
ncm@cantrip.org