[fpc-devel] Re: systemh.inc InterLockedIncrement64 (var Target: int64)

[Jeppe Johansen]

Den 28-10-2010 10:11, Florian Klaempfl skrev:
> Am 28.10.2010 10:02, schrieb Jeppe Johansen:
>> Den 27-10-2010 23:14, Florian Klämpfl skrev:
>>> Am 27.10.2010 22:52, schrieb Andrew Brunner:
>>>> My SCS project which is a scalable unified collaboration and
>>>> communication server that uses counting for transactions and network
>>>> consumption across all implemented protocols.  Bytes, when aggregated
>>>> can clearly exceed the 2GB limitation within seconds.  Partial
>>>> transactions (PTX) can exceed over 30,000 per second and full
>>>> transactions (TX) are typically 50% of that... But these numbers need
>>>> to add up.  Meaning the aggregate TX count must be of some proportion
>>>> of the PTX otherwise they are bogus.
>>>>
>>>> Int64 or QWord w/o locking or CAS is a serious issue for me.  I
>>>> absolutely need this feature or my transaction/byte counts will be off
>>>> per node per cluster and can lead to misinformation in the consumption
>>>> reports.
>>>>
>>>> For the time being though I can restrict the scale on i386
>>>> architecture since I tried to re-map the methods in the system.inc
>>>> file to no avail.  It appears that FPC does not include the
>>>> Interlocked*64 methods inside the RTL.
>>> I propose to add the 64 bit CAS for all 32 bit archs (if available): the
>>> 64 bit CAS instruction on a 32 bit target makes makes a lot "lock-free"
>>> algorithms simpler.
>>>
>>> So you can build your 64 bit interlockedincrement yourself (there is no
>>> native on any 32 bit target I'am aware of).
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>> CMPXCHG8B works on probably most x86 architectures
> Yes. That's what I wrote ;) because there is no interlockedincrement,
> one can use the 64 Bit CAS (implemented by CMPXCHG8B) to do the
> interlockedincrement64. But I don't want to provide a
> interlockedincrement64 on 32 bit platfroms by default because it
> requires cas with a while loop so it actually polls.
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Ah, *Increment. Sorry, was a bit quick there :)