[petsc-users] Streams scaling.log

[Manuel Valera]

Hi and thanks for the quick answer,

Yes it looks i am using MPICH for my configure instead of using the system
installation of OpenMPI, in the past i had better experience using MPICH
but maybe this will be a conflict, should i reconfigure using the system
MPI installation?

I solved the problem in a different way by login into the nodes i wanted to
use and doing the make streams tests there, but i get the following:

np  speedup
1 1.0
2 1.51
3 2.17
4 2.66
5 2.87
6 3.06
7 3.44
8 3.84
9 3.81
10 3.17
11 3.69
12 3.81
13 3.26
14 3.51
15 3.61
16 3.81
17 3.8
18 3.64
19 3.48
20 4.01

So very modest scaling, this is about the same i get with my application,
how can i make it work faster? i am already using --map-by and
--machinefile arguments for mpirun, maybe this is also a conflict with the
different MPI installations?

Thanks,



On Wed, Apr 25, 2018 at 11:51 AM, Karl Rupp <rupp at iue.tuwien.ac.at> wrote:

> Hi Manuel,
>
> this looks like the wrong MPI gets used. You should see an increasing
> number of processes, e.g.
>
> Number of MPI processes 1 Processor names  node37
> Triad:         6052.3571   Rate (MB/s)
> Number of MPI processes 2 Processor names  node37 node37
> Triad:        9138.9376   Rate (MB/s)
> Number of MPI processes 3 Processor names  node37 node37 node37
> Triad:        11077.5905   Rate (MB/s)
> Number of MPI processes 4 Processor names  node37 node37 node37 node37
> Triad:        12055.9123   Rate (MB/s)
>
> Best regards,
> Karli
>
>
>
>
> On 04/25/2018 08:26 PM, Manuel Valera wrote:
>
>> Hi,
>>
>> I'm running scaling tests on my system to check why my scaling is so
>> poor, and after following the MPIVersion guidelines my scaling.log output
>> looks like this:
>>
>> Number of MPI processes 1 Processor names  node37
>> Triad:        12856.9252   Rate (MB/s)
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Triad:         9138.3320   Rate (MB/s)
>> Triad:         9945.0006   Rate (MB/s)
>> Triad:        10480.8471   Rate (MB/s)
>> Triad:        12055.4846   Rate (MB/s)
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Triad:         7394.1014   Rate (MB/s)
>> Triad:         5528.9757   Rate (MB/s)
>> Triad:         6052.7506   Rate (MB/s)
>> Triad:         6188.5710   Rate (MB/s)
>> Triad:         6944.4515   Rate (MB/s)
>> Triad:         7407.1594   Rate (MB/s)
>> Triad:         9508.1984   Rate (MB/s)
>> Triad:        10699.7551   Rate (MB/s)
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Number of MPI processes 1 Processor names  node37
>> Triad:         6682.3749   Rate (MB/s)
>> Triad:         6825.3243   Rate (MB/s)
>> Triad:         7217.8178   Rate (MB/s)
>> Triad:         7525.1025   Rate (MB/s)
>> Triad:         7882.1781   Rate (MB/s)
>> Triad:         8071.1430   Rate (MB/s)
>> Triad:        10341.9424   Rate (MB/s)
>> Triad:        10418.4740   Rate (MB/s)
>>
>>
>> Is this normal? i feel is different from what i get from an usual streams
>> test, how can i get it to work properly?
>>
>> Thanks,
>>
>>
>>
>>
>>
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