A few points in addition to what has already been said:
1. You can always post a receive for size N when the actual message is
<=N. You can use this fact to pre-post a receive with size N, where N
is large enough for the header and a medium-sized message. If you
have a short message, it'l
> Date: Thu, 4 Jun 2009 11:14:16 +1000
> From: Lars Andersson
> Subject: [OMPI users] Receiving MPI messages of unknown size
> To: us...@open-mpi.org
>
> When using blocking message passing, I have simply solved the problem
> by first sending a small, fixed size header containing the size of
> re
> On Thu, 2009-06-04 at 14:54 +1000, Lars Andersson wrote:
>> Hi Gus,
>>
>> Thanks for the suggestion. I've been thinking along those lines, but
>> it seems to have drawbacks. Consider the following MPI conversation:
>>
>> Time NODE 1 NODE 2
>> 0 local work local work
On Thu, 2009-06-04 at 14:54 +1000, Lars Andersson wrote:
> Hi Gus,
>
> Thanks for the suggestion. I've been thinking along those lines, but
> it seems to have drawbacks. Consider the following MPI conversation:
>
> TimeNODE 1 NODE 2
> 0local work
On Thu, Jun 4, 2009 at 2:54 PM, Lars Andersson wrote:
> Hi Gus,
>
> Thanks for the suggestion. I've been thinking along those lines, but
> it seems to have drawbacks. Consider the following MPI conversation:
>
> Time NODE 1 NODE 2
> 0 local work
Hi Gus,
Thanks for the suggestion. I've been thinking along those lines, but
it seems to have drawbacks. Consider the following MPI conversation:
TimeNODE 1 NODE 2
0local work local work
1post n-b recv
Hi Lars
I wonder if you could always use blocking message passing on the
preliminary send/receive pair that transmits the message size/header,
then use non-blocking mode for the actual message.
If the "message size/header" part transmits a small buffer,
the preliminary send/recv pair will use t
