Russell King <[EMAIL PROTECTED]> wrote:
> On Sat, Dec 17, 2005 at 12:01:27AM +1100, Nick Piggin wrote:
>> You were proposing a worse default, which is the reason I suggested
>> it.
>
> I'd like to qualify that. "for architectures with native cmpxchg".
>
> For general consumption (not specifically related to mutex stuff)...
>
> For architectures with llsc, sequences stuch as:
>
> load
> modify
> cmpxchg
>
> are inefficient because they have to be implemented as:
>
> load
> modify
> load
> compare
> store conditional
>
I dont know what arch u have in mind but for ppc it is:
load-reserve
modify
store-conditional
and NOT the sequence you show.
--
Linh Dang
