[SimGrid-user] SMPI tracing

Ali Omar Abdelazim Mohammed ali.mohammed at unibas.ch
Wed Jun 14 13:53:49 CEST 2017

Dear Mr. Degomme,

Thank you very much, for all your answers.

I did what you suggested in 1. and it works fine.


On 13 Jun 2017, at 16:01, degomme <augustin.degomme at unibas.ch<mailto:augustin.degomme at unibas.ch>> wrote:


1. I think this happens if arguments are used before the call to MPI_Init(argc, argv) is done, as we may "fix" the argument list at this moment (we add some specific arguments at the start for MPI_Init to read, and they are then removed.. The 1 you see must be the ).  Could you put this call at the start of your program ? it should not change its behavior.

2. Gf type units are only supported in platform description, not in configuration options I think, but indeed having it would be nice.

3. The last number is optional, and represents the datatype used. If absent, it is assumed to be MPI_BYTE and the count of elements will represent the size of the message, but in some tracing tools it can be different. You can check decode_datatype or encode_datatype functions in src/smpi/smpi_replay.cpp for the list (0 is MPI_DOUBLE, 1 is MPI_INT).

Best regards,


On 13/06/2017 13:20, Ali Omar Abdelazim Mohammed wrote:

I have few questions/issues regarding simp simulations:

1. Parameters passed to the simulated application seems to be lost, and the arguments seems to get a default value, for example I run my program as:

smpirun -np 9 -platform xeon_platform.xml -hostfile hosts_test --cfg=smpi/host-speed:38300000000 ./ObjectLoaderTest 8000 5 0.1 0.5 0 Roff 1

However, my application complains that input parameters are not correct, for example arg[1] which is 8000 is read as 1.

So how to pass the parameters to the simulated application correctly

2. Setting the smpi/host-speed does not accept for example 38.3Gf, therefore I have to use --cfg=smpi/host-speed:38300000000. I tried also setting it in the platform file using configuration tags, but also Gf is not accepted. Is there a method to pass the units as the speed in the platform file ?

3. I generated a time independent trace of my application. I am wondering on the format of the trace, I got for example:

0 send 6 2478798 0
0 send 6 2478798 0
0 send 7 1 1
0 send 7 826266 0
0 send 7 826266 0
0 send 7 826266 0
0 compute 25885

I understand from this paper “Simulation of MPI Applications with Time-Independent Traces” at https://hal.inria.fr/hal-01064561/document that

1. The first number is the my rank
2. send/recv MPI call
3. source/dest rank
4. bytes sent/received
5. I could not find information what the last number represents, could you clarify this for me?

Thanks for your help,


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