what's the point of rpython?

[Brendan Miller]

On Wed, Jan 21, 2009 at 8:19 AM, Scott David Daniels
<Scott.Daniels at acm.org> wrote:
> Brendan Miller wrote:
>>
>> On Tue, Jan 20, 2009 at 10:03 PM, Paul Rubin
>> <"http://phr.cx"@nospam.invalid> wrote:
>>>
>>> ....  Of course I'm aware of the LOCK prefix but it slows
>>> down the instruction enormously compared with a non-locked instruction.
>>
>> I'm curious about that. I've been looking around for timing
>> information on the lock signal, but am having some trouble finding
>> them. Intuitively, given that the processor is much faster than the
>> bus, and you are just waiting for processor to complete an addition or
>> comparison before put the new memory value on the bus, it seems like
>> there should be very little additional bus contention vs a normal add
>> instruction.
>
> The opcode cannot simply talk to its cache, it must either go directly
> to off-chip memory or communicate to other processors that it (and it
> alone) owns the increment target.

Oh, right. *light bulb goes on* I wasn't thinking about cache at all.