[mpich-discuss] Message ordering with mpich

[James Edmondson]

Does synchronous MPI_Ssend/MPI_Recv really accomplish this? I would
think that a custom solution would be required for a global ordering,
one that actually maintains lamport clocks and breaks ties with
process identifiers, or something similar - like a sequencer, which is
less efficient because it requires a bottleneck akin to a token
authority for the next entity in the global total order.

Similarly, causal ordering could be supported with vectorized data
types to keep track of the causal ordering (current receipt clocks
from P0, P1, etc.). If you have some links to where the standard
supports global ordering via MPI_Ssend/MPI_Recv or how this might be
accomplished without a custom solution, would you mind sharing some
links? Or are you saying that MPI_Ssend ensures FIFO channels between
each entity? Because the latter doesn't imply any type of total
ordering (e.g. if P0 sent a message before P1 sent a message, then P3
receives and processes P0's message before P1.)

Thanks,
James Edmondson
Vanderbilt University ISIS


On Tue, Mar 8, 2011 at 4:35 PM, James Dinan <dinan at mcs.anl.gov> wrote:
> I think you should be able to achieve this with synchronous
> MPI_Ssend/MPI_Recv.
>
>  ~Jim.
>
> On 3/8/11 8:56 AM, h banki wrote:
>>
>> Hi,
>>
>> I want to send messages in total ordering between processes, how can I
>> do this? is there any special code?
>>
>>
>>
>> --- On *Tue, 3/8/11, Darius Buntinas /<buntinas at mcs.anl.gov>/* wrote:
>>
>>
>>    From: Darius Buntinas <buntinas at mcs.anl.gov>
>>    Subject: Re: [mpich-discuss] Message ordering with mpich
>>    To: mpich-discuss at mcs.anl.gov
>>    Date: Tuesday, March 8, 2011, 8:43 AM
>>
>>
>>    In MPI, all messages between two processes sent on the same
>>    communicator are FIFO ordered.
>>
>>    -d
>>
>>    On Mar 8, 2011, at 8:30 AM, h banki wrote:
>>
>>     > Hello,
>>     >
>>     > I want to know that is there any way to implement message
>>    ordering (FIFO, Total, Causal) with mpich?
>>     > is there any document about this issue?
>>     >
>>     > Regards,
>>     > Banki
>>     >
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