Barry,

The outputs are attached. I do not see a big difference from the
earlier results as you mentioned.

Let me know if there exist a similar benchmark that might help.

Vijay

On Thu, Feb 3, 2011 at 4:00 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>
> ? Hmm, just running the basic version with mpiexec -n 2 processes isn't that 
> useful because there is nothing to make sure they are both running at exactly 
> the same time.
>
> ? I've attached a new version of BasicVersion.c that attempts to synchronize 
> the operations in the two processes using MPI_Barrier()
> ; it is probably not a great way to do it, but better than nothing. Please 
> try that one.
>
> ? ?Thanks
>
>
> ? Barry
>
>
> On Feb 3, 2011, at 1:41 PM, Vijay S. Mahadevan wrote:
>
>> Barry,
>>
>> Thanks for the quick reply. I ran the benchmark/stream/BasicVersion
>> for one and two processes and the output are as follows:
>>
>> -n 1
>> -------------------------------------------------------------
>> This system uses 8 bytes per DOUBLE PRECISION word.
>> -------------------------------------------------------------
>> Array size = 2000000, Offset = 0
>> Total memory required = 45.8 MB.
>> Each test is run 50 times, but only
>> the *best* time for each is used.
>> -------------------------------------------------------------
>> Your clock granularity/precision appears to be 1 microseconds.
>> Each test below will take on the order of 2529 microseconds.
>> ? (= 2529 clock ticks)
>> Increase the size of the arrays if this shows that
>> you are not getting at least 20 clock ticks per test.
>> -------------------------------------------------------------
>> WARNING -- The above is only a rough guideline.
>> For best results, please be sure you know the
>> precision of your system timer.
>> -------------------------------------------------------------
>> Function ? ? ?Rate (MB/s) ? RMS time ? ? Min time ? ? Max time
>> Copy: ? ? ? 10161.8510 ? ? ? 0.0032 ? ? ? 0.0031 ? ? ? 0.0037
>> Scale: ? ? ? 9843.6177 ? ? ? 0.0034 ? ? ? 0.0033 ? ? ? 0.0038
>> Add: ? ? ? ?10656.7114 ? ? ? 0.0046 ? ? ? 0.0045 ? ? ? 0.0053
>> Triad: ? ? ?10799.0448 ? ? ? 0.0046 ? ? ? 0.0044 ? ? ? 0.0054
>>
>> -n 2
>> -------------------------------------------------------------
>> This system uses 8 bytes per DOUBLE PRECISION word.
>> -------------------------------------------------------------
>> Array size = 2000000, Offset = 0
>> Total memory required = 45.8 MB.
>> Each test is run 50 times, but only
>> the *best* time for each is used.
>> -------------------------------------------------------------
>> Your clock granularity/precision appears to be 1 microseconds.
>> Each test below will take on the order of 4320 microseconds.
>> ? (= 4320 clock ticks)
>> Increase the size of the arrays if this shows that
>> you are not getting at least 20 clock ticks per test.
>> -------------------------------------------------------------
>> WARNING -- The above is only a rough guideline.
>> For best results, please be sure you know the
>> precision of your system timer.
>> -------------------------------------------------------------
>> Function ? ? ?Rate (MB/s) ? RMS time ? ? Min time ? ? Max time
>> Copy: ? ? ? ?5739.9704 ? ? ? 0.0058 ? ? ? 0.0056 ? ? ? 0.0063
>> Scale: ? ? ? 5839.3617 ? ? ? 0.0058 ? ? ? 0.0055 ? ? ? 0.0062
>> Add: ? ? ? ? 6116.9323 ? ? ? 0.0081 ? ? ? 0.0078 ? ? ? 0.0085
>> Triad: ? ? ? 6021.0722 ? ? ? 0.0084 ? ? ? 0.0080 ? ? ? 0.0088
>> -------------------------------------------------------------
>> This system uses 8 bytes per DOUBLE PRECISION word.
>> -------------------------------------------------------------
>> Array size = 2000000, Offset = 0
>> Total memory required = 45.8 MB.
>> Each test is run 50 times, but only
>> the *best* time for each is used.
>> -------------------------------------------------------------
>> Your clock granularity/precision appears to be 1 microseconds.
>> Each test below will take on the order of 2954 microseconds.
>> ? (= 2954 clock ticks)
>> Increase the size of the arrays if this shows that
>> you are not getting at least 20 clock ticks per test.
>> -------------------------------------------------------------
>> WARNING -- The above is only a rough guideline.
>> For best results, please be sure you know the
>> precision of your system timer.
>> -------------------------------------------------------------
>> Function ? ? ?Rate (MB/s) ? RMS time ? ? Min time ? ? Max time
>> Copy: ? ? ? ?6091.9448 ? ? ? 0.0056 ? ? ? 0.0053 ? ? ? 0.0061
>> Scale: ? ? ? 5501.1775 ? ? ? 0.0060 ? ? ? 0.0058 ? ? ? 0.0062
>> Add: ? ? ? ? 5960.4640 ? ? ? 0.0084 ? ? ? 0.0081 ? ? ? 0.0087
>> Triad: ? ? ? 5936.2109 ? ? ? 0.0083 ? ? ? 0.0081 ? ? ? 0.0089
>>
>> I do not have OpenMP installed and so not sure if you wanted that when
>> you said two threads. I also closed most of the applications that were
>> open before running these tests and so they should hopefully be
>> accurate.
>>
>> Vijay
>>
>>
>> On Thu, Feb 3, 2011 at 1:17 PM, Barry Smith <bsmith at mcs.anl.gov> wrote:
>>>
>>> ?Vljay
>>>
>>> ? Let's just look at a single embarrassingly parallel computation in the 
>>> run, this computation has NO communication and uses NO MPI and NO 
>>> synchronization between processes
>>>
>>> ------------------------------------------------------------------------------------------------------------------------
>>> Event ? ? ? ? ? ? ? ?Count ? ? ?Time (sec) ? ? Flops ? ? ? ? ? ? ? ? ? ? ? 
>>> ? ? ? --- Global --- ?--- Stage --- ? Total
>>> ? ? ? ? ? ? ? ? ? Max Ratio ?Max ? ? Ratio ? Max ?Ratio ?Mess ? Avg len 
>>> Reduct ?%T %F %M %L %R ?%T %F %M %L %R Mflop/s
>>> ------------------------------------------------------------------------------------------------------------------------
>>>
>>> ?1 process
>>> VecMAXPY ? ? ? ? ? ?3898 1.0 1.7074e+01 1.0 3.39e+10 1.0 0.0e+00 0.0e+00 
>>> 0.0e+00 15 20 ?0 ?0 ?0 ?29 40 ?0 ?0 ?0 ?1983
>>>
>>> ?2 processes
>>> VecMAXPY ? ? ? ? ? ?3898 1.0 1.3861e+01 1.0 1.72e+10 1.0 0.0e+00 0.0e+00 
>>> 0.0e+00 15 20 ?0 ?0 ?0 ?31 40 ?0 ?0 ?0 ?2443
>>>
>>> ? The speed up is 1.7074e+01/1.3861e+01 = 2443./1983 = 1.23 ?which is 
>>> terrible! Now why would it be so bad (remember you cannot blame MPI)
>>>
>>> 1) other processes are running on the machine sucking up memory bandwidth. 
>>> Make sure no other compute tasks are running during this time.
>>>
>>> 2) the single process run is able to use almost all of the hardware memory 
>>> bandwidth, so introducing the second process cannot increase the 
>>> performance much. This means this machine is terrible for parallelization 
>>> of sparse iterative solvers.
>>>
>>> 3) the machine is somehow misconfigured (beats me how) so that while the 
>>> one process job doesn't use more than half of the memory bandwidth, when 
>>> two processes are run the second process cannot utilize all that additional 
>>> memory bandwidth.
>>>
>>> ?In src/benchmarks/streams you can run make test and have it generate a 
>>> report of how the streams benchmark is able to utilize the memory 
>>> bandwidth. Run that and send us the output (run with just 2 threads).
>>>
>>> ? Barry
>>>
>>>
>>> On Feb 3, 2011, at 12:05 PM, Vijay S. Mahadevan wrote:
>>>
>>>> Matt,
>>>>
>>>> I apologize for the incomplete information. Find attached the
>>>> log_summary for all the cases.
>>>>
>>>> The dual quad-core system has 12 GB DDR3 SDRAM at 1333MHz with
>>>> 2x2GB/2x4GB configuration. I do not know how to decipher the memory
>>>> bandwidth with this information but if you need anything more, do let
>>>> me know.
>>>>
>>>> VIjay
>>>>
>>>> On Thu, Feb 3, 2011 at 11:42 AM, Matthew Knepley <knepley at gmail.com> 
>>>> wrote:
>>>>> On Thu, Feb 3, 2011 at 11:37 AM, Vijay S. Mahadevan <vijay.m at gmail.com>
>>>>> wrote:
>>>>>>
>>>>>> Barry,
>>>>>>
>>>>>> Sorry about the delay in the reply. I did not have access to the
>>>>>> system to test out what you said, until now.
>>>>>>
>>>>>> I tried with -dmmg_nlevels 5, along with the default setup: ./ex20
>>>>>> -log_summary -dmmg_view -pc_type jacobi -dmmg_nlevels 5
>>>>>>
>>>>>> processor ? ? ? time
>>>>>> 1 ? ? ? ? ? ? ? ? ? ? ?114.2
>>>>>> 2 ? ? ? ? ? ? ? ? ? ? ?89.45
>>>>>> 4 ? ? ? ? ? ? ? ? ? ? ?81.01
>>>>>
>>>>> 1) ALWAYS ALWAYS send the full -log_summary. I cannot tell anything from
>>>>> this data.
>>>>> 2) Do you know the memory bandwidth characteristics of this machine? That 
>>>>> is
>>>>> crucial and
>>>>> ? ? you cannot begin to understand speedup on it until you do. Please look
>>>>> this up.
>>>>> 3) Worrying about specifics of the MPI implementation makes no sense until
>>>>> the basics are nailed down.
>>>>> ? ?Matt
>>>>>
>>>>>>
>>>>>> The scaleup doesn't seem to be optimal, even with two processors. I am
>>>>>> wondering if the fault is in the MPI configuration itself. Are these
>>>>>> results as you would expect ? I can also send you the log_summary for
>>>>>> all cases if that will help.
>>>>>>
>>>>>> Vijay
>>>>>>
>>>>>> On Thu, Feb 3, 2011 at 11:10 AM, Barry Smith <bsmith at mcs.anl.gov> 
>>>>>> wrote:
>>>>>>>
>>>>>>> On Feb 2, 2011, at 11:13 PM, Vijay S. Mahadevan wrote:
>>>>>>>
>>>>>>>> Barry,
>>>>>>>>
>>>>>>>> I understand what you are saying but which example/options then is the
>>>>>>>> best one to compute the scalability in a multi-core machine ? I chose
>>>>>>>> the nonlinear diffusion problem specifically because of its inherent
>>>>>>>> stiffness that could lead probably provide noticeable scalability in a
>>>>>>>> multi-core system. From your experience, do you think there is another
>>>>>>>> example program that will demonstrate this much more rigorously or
>>>>>>>> clearly ? Btw, I dont get good speedup even for 2 processes with
>>>>>>>> ex20.c and that was the original motivation for this thread.
>>>>>>>
>>>>>>> ? Did you follow my instructions?
>>>>>>>
>>>>>>> ? Barry
>>>>>>>
>>>>>>>>
>>>>>>>> Satish. I configured with --download-mpich now without the
>>>>>>>> mpich-device. The results are given above. I will try with the options
>>>>>>>> you provided although I dont entirely understand what they mean, which
>>>>>>>> kinda bugs me.. Also is OpenMPI the preferred implementation in Ubuntu
>>>>>>>> ?
>>>>>>>>
>>>>>>>> Vijay
>>>>>>>>
>>>>>>>> On Wed, Feb 2, 2011 at 6:35 PM, Barry Smith <bsmith at mcs.anl.gov> 
>>>>>>>> wrote:
>>>>>>>>>
>>>>>>>>> ? Ok, everything makes sense. Looks like you are using two level
>>>>>>>>> multigrid (coarse grid 20 by 20 by 20) with -mg_coarse_pc_type 
>>>>>>>>> redundant
>>>>>>>>> -mg_coarse_redundant_pc_type lu ?This means it is solving the coarse 
>>>>>>>>> grid
>>>>>>>>> problem redundantly on each process (each process is solving the 
>>>>>>>>> entire
>>>>>>>>> coarse grid solve using LU factorization). The time for the 
>>>>>>>>> factorization is
>>>>>>>>> (in the two process case)
>>>>>>>>>
>>>>>>>>> MatLUFactorNum ? ? ? ?14 1.0 2.9096e+00 1.0 1.90e+09 1.0 0.0e+00
>>>>>>>>> 0.0e+00 0.0e+00 37 41 ?0 ?0 ?0 ?74 82 ?0 ?0 ?0 ?1307
>>>>>>>>> MatILUFactorSym ? ? ? ?7 1.0 7.2970e-03 1.1 0.00e+00 0.0 0.0e+00
>>>>>>>>> 0.0e+00 7.0e+00 ?0 ?0 ?0 ?0 ?1 ? 0 ?0 ?0 ?0 ?2 ? ? 0
>>>>>>>>>
>>>>>>>>> which is 74 percent of the total solve time (and 84 percent of the
>>>>>>>>> flops). ? When 3/4th of the entire run is not parallel at all you 
>>>>>>>>> cannot
>>>>>>>>> expect much speedup. ?If you run with -snes_view it will display 
>>>>>>>>> exactly the
>>>>>>>>> solver being used. You cannot expect to understand the performance if 
>>>>>>>>> you
>>>>>>>>> don't understand what the solver is actually doing. Using a 20 by 20 
>>>>>>>>> by 20
>>>>>>>>> coarse grid is generally a bad idea since the code spends most of the 
>>>>>>>>> time
>>>>>>>>> there, stick with something like 5 by 5 by 5.
>>>>>>>>>
>>>>>>>>> ?Suggest running with the default grid and -dmmg_nlevels 5 now the
>>>>>>>>> percent in the coarse solve will be a trivial percent of the run time.
>>>>>>>>>
>>>>>>>>> ?You should get pretty good speed up for 2 processes but not much
>>>>>>>>> better speedup for four processes because as Matt noted the 
>>>>>>>>> computation is
>>>>>>>>> memory bandwidth limited;
>>>>>>>>> http://www.mcs.anl.gov/petsc/petsc-as/documentation/faq.html#computers.
>>>>>>>>>  Note
>>>>>>>>> also that this is running multigrid which is a fast solver, but 
>>>>>>>>> doesn't
>>>>>>>>> parallel scale as well many slow algorithms. For example if you run
>>>>>>>>> -dmmg_nlevels 5 -pc_type jacobi you will get great speed up with 2
>>>>>>>>> processors but crummy speed.
>>>>>>>>>
>>>>>>>>> ?Barry
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> On Feb 2, 2011, at 6:17 PM, Vijay S. Mahadevan wrote:
>>>>>>>>>
>>>>>>>>>> Barry,
>>>>>>>>>>
>>>>>>>>>> Please find attached the patch for the minor change to control the
>>>>>>>>>> number of elements from command line for snes/ex20.c. I know that
>>>>>>>>>> this
>>>>>>>>>> can be achieved with -grid_x etc from command_line but thought this
>>>>>>>>>> just made the typing for the refinement process a little easier. I
>>>>>>>>>> apologize if there was any confusion.
>>>>>>>>>>
>>>>>>>>>> Also, find attached the full log summaries for -np=1 and -np=2.
>>>>>>>>>> Thanks.
>>>>>>>>>>
>>>>>>>>>> Vijay
>>>>>>>>>>
>>>>>>>>>> On Wed, Feb 2, 2011 at 6:06 PM, Barry Smith <bsmith at mcs.anl.gov>
>>>>>>>>>> wrote:
>>>>>>>>>>>
>>>>>>>>>>> ?We need all the information from -log_summary to see what is going
>>>>>>>>>>> on.
>>>>>>>>>>>
>>>>>>>>>>> ?Not sure what -grid 20 means but don't expect any good parallel
>>>>>>>>>>> performance with less than at least 10,000 unknowns per process.
>>>>>>>>>>>
>>>>>>>>>>> ? Barry
>>>>>>>>>>>
>>>>>>>>>>> On Feb 2, 2011, at 5:38 PM, Vijay S. Mahadevan wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Here's the performance statistic on 1 and 2 processor runs.
>>>>>>>>>>>>
>>>>>>>>>>>> /usr/lib/petsc/linux-gnu-cxx-opt/bin/mpiexec -n 1 ./ex20 -grid 20
>>>>>>>>>>>> -log_summary
>>>>>>>>>>>>
>>>>>>>>>>>> ? ? ? ? ? ? ? ? ? ? ? ? Max ? ? ? Max/Min ? ? ? ?Avg ? ? ?Total
>>>>>>>>>>>> Time (sec): ? ? ? ? ? 8.452e+00 ? ? ?1.00000 ? 8.452e+00
>>>>>>>>>>>> Objects: ? ? ? ? ? ? ?1.470e+02 ? ? ?1.00000 ? 1.470e+02
>>>>>>>>>>>> Flops: ? ? ? ? ? ? ? ?5.045e+09 ? ? ?1.00000 ? 5.045e+09 ?5.045e+09
>>>>>>>>>>>> Flops/sec: ? ? ? ? ? ?5.969e+08 ? ? ?1.00000 ? 5.969e+08 ?5.969e+08
>>>>>>>>>>>> MPI Messages: ? ? ? ? 0.000e+00 ? ? ?0.00000 ? 0.000e+00 ?0.000e+00
>>>>>>>>>>>> MPI Message Lengths: ?0.000e+00 ? ? ?0.00000 ? 0.000e+00 ?0.000e+00
>>>>>>>>>>>> MPI Reductions: ? ? ? 4.440e+02 ? ? ?1.00000
>>>>>>>>>>>>
>>>>>>>>>>>> /usr/lib/petsc/linux-gnu-cxx-opt/bin/mpiexec -n 2 ./ex20 -grid 20
>>>>>>>>>>>> -log_summary
>>>>>>>>>>>>
>>>>>>>>>>>> ? ? ? ? ? ? ? ? ? ? ? ? Max ? ? ? Max/Min ? ? ? ?Avg ? ? ?Total
>>>>>>>>>>>> Time (sec): ? ? ? ? ? 7.851e+00 ? ? ?1.00000 ? 7.851e+00
>>>>>>>>>>>> Objects: ? ? ? ? ? ? ?2.000e+02 ? ? ?1.00000 ? 2.000e+02
>>>>>>>>>>>> Flops: ? ? ? ? ? ? ? ?4.670e+09 ? ? ?1.00580 ? 4.657e+09 ?9.313e+09
>>>>>>>>>>>> Flops/sec: ? ? ? ? ? ?5.948e+08 ? ? ?1.00580 ? 5.931e+08 ?1.186e+09
>>>>>>>>>>>> MPI Messages: ? ? ? ? 7.965e+02 ? ? ?1.00000 ? 7.965e+02 ?1.593e+03
>>>>>>>>>>>> MPI Message Lengths: ?1.412e+07 ? ? ?1.00000 ? 1.773e+04 ?2.824e+07
>>>>>>>>>>>> MPI Reductions: ? ? ? 1.046e+03 ? ? ?1.00000
>>>>>>>>>>>>
>>>>>>>>>>>> I am not entirely sure if I can make sense out of that statistic
>>>>>>>>>>>> but
>>>>>>>>>>>> if there is something more you need, please feel free to let me
>>>>>>>>>>>> know.
>>>>>>>>>>>>
>>>>>>>>>>>> Vijay
>>>>>>>>>>>>
>>>>>>>>>>>> On Wed, Feb 2, 2011 at 5:15 PM, Matthew Knepley <knepley at 
>>>>>>>>>>>> gmail.com>
>>>>>>>>>>>> wrote:
>>>>>>>>>>>>> On Wed, Feb 2, 2011 at 5:04 PM, Vijay S. Mahadevan
>>>>>>>>>>>>> <vijay.m at gmail.com>
>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Matt,
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> The -with-debugging=1 option is certainly not meant for
>>>>>>>>>>>>>> performance
>>>>>>>>>>>>>> studies but I didn't expect it to yield the same cpu time as a
>>>>>>>>>>>>>> single
>>>>>>>>>>>>>> processor for snes/ex20 i.e., my runs with 1 and 2 processors
>>>>>>>>>>>>>> take
>>>>>>>>>>>>>> approximately the same amount of time for computation of
>>>>>>>>>>>>>> solution. But
>>>>>>>>>>>>>> I am currently configuring without debugging symbols and shall
>>>>>>>>>>>>>> let you
>>>>>>>>>>>>>> know what that yields.
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On a similar note, is there something extra that needs to be done
>>>>>>>>>>>>>> to
>>>>>>>>>>>>>> make use of multi-core machines while using MPI ? I am not sure
>>>>>>>>>>>>>> if
>>>>>>>>>>>>>> this is even related to PETSc but could be an MPI configuration
>>>>>>>>>>>>>> option
>>>>>>>>>>>>>> that maybe either I or the configure process is missing. All
>>>>>>>>>>>>>> ideas are
>>>>>>>>>>>>>> much appreciated.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Sparse MatVec (MatMult) is a memory bandwidth limited operation.
>>>>>>>>>>>>> On most
>>>>>>>>>>>>> cheap multicore machines, there is a single memory bus, and thus
>>>>>>>>>>>>> using more
>>>>>>>>>>>>> cores gains you very little extra performance. I still suspect you
>>>>>>>>>>>>> are not
>>>>>>>>>>>>> actually
>>>>>>>>>>>>> running in parallel, because you usually see a small speedup. That
>>>>>>>>>>>>> is why I
>>>>>>>>>>>>> suggested looking at -log_summary since it tells you how many
>>>>>>>>>>>>> processes were
>>>>>>>>>>>>> run and breaks down the time.
>>>>>>>>>>>>> ? ?Matt
>>>>>>>>>>>>>
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> Vijay
>>>>>>>>>>>>>>
>>>>>>>>>>>>>> On Wed, Feb 2, 2011 at 4:53 PM, Matthew Knepley
>>>>>>>>>>>>>> <knepley at gmail.com> wrote:
>>>>>>>>>>>>>>> On Wed, Feb 2, 2011 at 4:46 PM, Vijay S. Mahadevan
>>>>>>>>>>>>>>> <vijay.m at gmail.com>
>>>>>>>>>>>>>>> wrote:
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Hi,
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> I am trying to configure my petsc install with an MPI
>>>>>>>>>>>>>>>> installation to
>>>>>>>>>>>>>>>> make use of a dual quad-core desktop system running Ubuntu. But
>>>>>>>>>>>>>>>> eventhough the configure/make process went through without
>>>>>>>>>>>>>>>> problems,
>>>>>>>>>>>>>>>> the scalability of the programs don't seem to reflect what I
>>>>>>>>>>>>>>>> expected.
>>>>>>>>>>>>>>>> My configure options are
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> --download-f-blas-lapack=1 --with-mpi-dir=/usr/lib/
>>>>>>>>>>>>>>>> --download-mpich=1
>>>>>>>>>>>>>>>> --with-mpi-shared=0 --with-shared=0 --COPTFLAGS=-g
>>>>>>>>>>>>>>>> --download-parmetis=1 --download-superlu_dist=1
>>>>>>>>>>>>>>>> --download-hypre=1
>>>>>>>>>>>>>>>> --download-blacs=1 --download-scalapack=1 --with-clanguage=C++
>>>>>>>>>>>>>>>> --download-plapack=1 --download-mumps=1 --download-umfpack=yes
>>>>>>>>>>>>>>>> --with-debugging=1 --with-errorchecking=yes
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> 1) For performance studies, make a build using
>>>>>>>>>>>>>>> --with-debugging=0
>>>>>>>>>>>>>>> 2) Look at -log_summary for a breakdown of performance
>>>>>>>>>>>>>>> ? ?Matt
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Is there something else that needs to be done as part of the
>>>>>>>>>>>>>>>> configure
>>>>>>>>>>>>>>>> process to enable a decent scaling ? I am only comparing
>>>>>>>>>>>>>>>> programs with
>>>>>>>>>>>>>>>> mpiexec (-n 1) and (-n 2) but they seem to be taking
>>>>>>>>>>>>>>>> approximately the
>>>>>>>>>>>>>>>> same time as noted from -log_summary. If it helps, I've been
>>>>>>>>>>>>>>>> testing
>>>>>>>>>>>>>>>> with snes/examples/tutorials/ex20.c for all purposes with a
>>>>>>>>>>>>>>>> custom
>>>>>>>>>>>>>>>> -grid parameter from command-line to control the number of
>>>>>>>>>>>>>>>> unknowns.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> If there is something you've witnessed before in this
>>>>>>>>>>>>>>>> configuration or
>>>>>>>>>>>>>>>> if you need anything else to analyze the problem, do let me
>>>>>>>>>>>>>>>> know.
>>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>> Thanks,
>>>>>>>>>>>>>>>> Vijay
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>>> --
>>>>>>>>>>>>>>> What most experimenters take for granted before they begin their
>>>>>>>>>>>>>>> experiments
>>>>>>>>>>>>>>> is infinitely more interesting than any results to which their
>>>>>>>>>>>>>>> experiments
>>>>>>>>>>>>>>> lead.
>>>>>>>>>>>>>>> -- Norbert Wiener
>>>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> --
>>>>>>>>>>>>> What most experimenters take for granted before they begin their
>>>>>>>>>>>>> experiments
>>>>>>>>>>>>> is infinitely more interesting than any results to which their
>>>>>>>>>>>>> experiments
>>>>>>>>>>>>> lead.
>>>>>>>>>>>>> -- Norbert Wiener
>>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>> <ex20.patch><ex20_np1.out><ex20_np2.out>
>>>>>>>>>
>>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>
>>>>>
>>>>>
>>>>> --
>>>>> What most experimenters take for granted before they begin their 
>>>>> experiments
>>>>> is infinitely more interesting than any results to which their experiments
>>>>> lead.
>>>>> -- Norbert Wiener
>>>>>
>>>> <ex20_np1.out><ex20_np2.out><ex20_np4.out>
>>>
>>>
>
>
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: basicversion_np1.out
Type: application/octet-stream
Size: 999 bytes
Desc: not available
URL: 
<http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110203/f2bb0611/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: basicversion_np2.out
Type: application/octet-stream
Size: 1999 bytes
Desc: not available
URL: 
<http://lists.mcs.anl.gov/pipermail/petsc-users/attachments/20110203/f2bb0611/attachment-0003.obj>

Reply via email to