what's the point of rpython?

[Rhodri James]

On Wed, 21 Jan 2009 02:29:01 -0000, Paul Rubin  
<"http://phr.cx"@nospam.invalid> wrote:

> "Rhodri James" <rhodri at wildebst.demon.co.uk> writes:
>> > What cpu's do you know of that can atomically increment and decrement
>> > integers without locking?
>>
>> x86 (and pretty much any 8080 derivative, come to think of it).
>
> It would not have occurred to me that "lock inc" increments "without
> locking".  I understand that's different from a lock value sitting in
> the data object but I thought that "lock-free algorithm" meant one
> that didn't assert any of these hardware locks either.  Maybe I'm
> wrong.

I tend to live in single-core worlds, so "inc" on its lonesome works
just fine.

>> Just do the locking properly and worry about optimisations later.
>
> That has already been tried, and found to be unacceptably slow for the
> purpose at hand.  Now we're looking for the optimizations.

In that case I'd second the suggestion of taking a long, hard look
at the Linux core locking and synchronisation primatives.

-- 
Rhodri James *-* Wildebeeste Herder to the Masses