Re: [OMPI users] MPI_AllReduce vs MPI_IAllReduce

2015-11-30 Thread Felipe .
Thanks for the reply, Ralph. Now I think it is clearer to me why it could be so much slower. The reason would be that the blocking algorithm for reduction has a implementation very different than the non-blocking. Since there are lots of ways to implement it, are there options to tune the non-blo

Re: [OMPI users] MPI_AllReduce vs MPI_IAllReduce

2015-11-27 Thread Ralph Castain
One thing you might want to keep in mind is that “non-blocking” doesn’t mean “asynchronous progress”. The API may not block, but the communications only progress whenever you actually call down into the library. So if you are calling a non-blocking collective, and then make additional calls int

Re: [OMPI users] MPI_AllReduce vs MPI_IAllReduce

2015-11-27 Thread Felipe .
>Try and do a variable amount of work for every process, I see non-blocking >as a way to speed-up communication if they arrive individually to the call. >Please always have this at the back of your mind when doing this. I tried to simplify the problem at the explanation. The "local_computation" is

Re: [OMPI users] MPI_AllReduce vs MPI_IAllReduce

2015-11-27 Thread Nick Papior
Try and do a variable amount of work for every process, I see non-blocking as a way to speed-up communication if they arrive individually to the call. Please always have this at the back of your mind when doing this. Surely non-blocking has overhead, and if the communication time is low, so will t

[OMPI users] MPI_AllReduce vs MPI_IAllReduce

2015-11-27 Thread Felipe .
Hello! I have a program that basically is (first implementation): for i in N: local_computation(i) mpi_allreduce(in_place, i) In order to try to mitigate the implicit barrier of the mpi_allreduce, I tried to start an mpi_Iallreduce. Like this(second implementation): for i in N: local_comput

Re: [OMPI users] MPI_Allreduce with F90 Handles

2012-11-30 Thread Jeff Squyres
On Nov 30, 2012, at 2:04 PM, Shane Hart wrote: > I've attached a small sample program that demonstrates the problem. You can > toggle working/non-working behaviour by toggling commenting on line 27. Thanks! I got swamped this week, but I'll try to look at it next week (although with the Forum

Re: [OMPI users] MPI_Allreduce with F90 Handles

2012-11-30 Thread Shane Hart
I've attached a small sample program that demonstrates the problem. You can toggle working/non-working behaviour by toggling commenting on line 27. I've tried to open a bug report, but the system isn't letting me register for Trac: Trac detected an internal error: KeyError: 'recaptcha_challeng

[OMPI users] MPI_Allreduce with F90 Handles

2012-11-29 Thread Shane Hart
All, I have a Fortran code that works quite well with OpenMPI 1.4.3 where I create a handle using: call MPI_TYPE_CREATE_F90_INTEGER(9, COMM_INT4, ierror) and then do a reduction with: call MPI_ALLREDUCE(send_buffer, buffer, count, COMM_INT4, MPI_SUM, communicator, ierror) Howev

Re: [OMPI users] MPI_Allreduce fail (minGW gfortran + OpenMPI 1.6.1)

2012-09-08 Thread Yonghui
Hi Jeff, Thanks for your response. Like you said, the code works for you in a Linux system. And I am sure that the code works on Linux and even Mac os x. But if you use MinGW (basically you have all gnu things on windows) to compile, the code abort when running to MPI_Allreduce. In my opinion

Re: [OMPI users] MPI_Allreduce fail (minGW gfortran + OpenMPI 1.6.1)

2012-09-08 Thread Jeff Squyres
I am unable to replicate your problem, but admittedly I only have access to gfortran on Linux. And I am definitely *not* a Fortran expert. :-\ The code seems to run fine for me -- can you send another test program that actually tests the results of the all reduce? Fortran allocatable stuff al

[OMPI users] MPI_Allreduce fail (minGW gfortran + OpenMPI 1.6.1)

2012-09-06 Thread Yonghui
Dear mpi users and developers, I am having some trouble with MPI_Allreduce. I am using MinGW (gcc 4.6.2) with OpenMPI 1.6.1. The MPI_Allreduce in c version works fine, but the fortran version failed with error. Here is the simple fortran code to reproduce the error: program ma

Re: [OMPI users] MPI_Allreduce hangs

2012-07-02 Thread Jeff Squyres
On Jun 27, 2012, at 6:32 PM, Martin Siegert wrote: > However, there is another issue that may affect the performance of the 1.6.1 > version. I see a LOT of the following messages on stderr: > > -- > The OpenFabrics (openib) B

Re: [OMPI users] MPI_Allreduce hangs

2012-06-27 Thread Martin Siegert
On Wed, Jun 27, 2012 at 02:30:11PM -0400, Jeff Squyres wrote: > On Jun 27, 2012, at 2:25 PM, Martin Siegert wrote: > > >> http://www.open-mpi.org/~jsquyres/unofficial/openmpi-1.6.1ticket3131r26612M.tar.bz2 > > > > Thanks! I tried this and, indeed, the program (I tested quantum espresso, > > pw.x,

Re: [OMPI users] MPI_Allreduce hangs

2012-06-27 Thread Jeff Squyres
On Jun 27, 2012, at 2:25 PM, Martin Siegert wrote: >> http://www.open-mpi.org/~jsquyres/unofficial/openmpi-1.6.1ticket3131r26612M.tar.bz2 > > Thanks! I tried this and, indeed, the program (I tested quantum espresso, > pw.x, so far) no longer hangs. Good! We're doing a bit more definitive testin

Re: [OMPI users] MPI_Allreduce hangs

2012-06-27 Thread Martin Siegert
Hi Jeff, On Wed, Jun 20, 2012 at 04:16:12PM -0400, Jeff Squyres wrote: > On Jun 20, 2012, at 3:36 PM, Martin Siegert wrote: > > > by now we know of three programs - dirac, wrf, quantum espresso - that > > all hang with openmpi-1.4.x (have not yet checked with openmpi-1.6). > > All of these progra

Re: [OMPI users] MPI_Allreduce hangs

2012-06-20 Thread Jeff Squyres
On Jun 20, 2012, at 3:36 PM, Martin Siegert wrote: > by now we know of three programs - dirac, wrf, quantum espresso - that > all hang with openmpi-1.4.x (have not yet checked with openmpi-1.6). > All of these programs run to completion with the mpiexec commandline > argument: --mca btl_openib_fla

Re: [OMPI users] MPI_Allreduce hangs

2012-06-20 Thread Martin Siegert
Hi, by now we know of three programs - dirac, wrf, quantum espresso - that all hang with openmpi-1.4.x (have not yet checked with openmpi-1.6). All of these programs run to completion with the mpiexec commandline argument: --mca btl_openib_flags 305 We now set this in the global configuration file

Re: [OMPI users] MPI_Allreduce hangs

2012-05-04 Thread Jorge Chiva Segura
Hello, I think that my problem: http://www.open-mpi.org/community/lists/users/2012/05/19182.php is similar to yours. Following the advice in the thread that you posted: http://www.open-mpi.org/community/lists/users/2011/07/16996.php I have tried to run my program adding: -mca btl_openib_flags 305

Re: [OMPI users] MPI_Allreduce hangs

2012-05-04 Thread Martin Siegert
On Tue, Apr 24, 2012 at 04:19:31PM -0400, Brock Palen wrote: > To throw in my $0.02, though it is worth less. > > Were you running this on verb based infiniband? Correct. > We see a problem that we have a work around for even with the newest 1.4.5 > only on IB, we can reproduce it with IMB. I

Re: [OMPI users] MPI_Allreduce hangs

2012-04-24 Thread Brock Palen
To throw in my $0.02, though it is worth less. Were you running this on verb based infiniband? We see a problem that we have a work around for even with the newest 1.4.5 only on IB, we can reproduce it with IMB. You can find an old thread from me about it. Your problem might not be the same.

Re: [OMPI users] MPI_Allreduce hangs

2012-04-24 Thread Jeffrey Squyres
Could you repeat your tests with 1.4.5 and/or 1.5.5? On Apr 23, 2012, at 1:32 PM, Martin Siegert wrote: > Hi, > > I am debugging a program that hangs in MPI_Allreduce (openmpi-1.4.3). > An strace of one of the processes shows: > > Process 10925 attached with 3 threads - interrupt to quit > [pi

Re: [OMPI users] MPI_Allreduce hangs

2012-04-23 Thread Gus Correa
Hi Martin Not sure this solution will help with your problem, but a workaround for situations where the count number exceeds the maximum 32-bit positive integer is to declare a user defined type, say MPI_Type_Contiguous or MPI_Type_Vector, large enough to aggregate a bunch of your original data (

[OMPI users] MPI_Allreduce hangs

2012-04-23 Thread Martin Siegert
Hi, I am debugging a program that hangs in MPI_Allreduce (openmpi-1.4.3). An strace of one of the processes shows: Process 10925 attached with 3 threads - interrupt to quit [pid 10927] poll([{fd=17, events=POLLIN}, {fd=16, events=POLLIN}], 2, -1 [pid 10926] select(15, [8 14], [], NULL, NULL [pi

[OMPI users] MPI_ALLREDUCE: Segmentation Fault

2011-06-02 Thread Timothy Stitt
Hi all, We have a code built with OpenMPI (v1.4.3) and the Intel v12.0 compiler that has been tested successfully on 10s - 100s of cores on our cluster. We recently ran the same code with 1020 cores and received the following runtime error: > [d6cneh042:28543] *** Process received signal *** >

Re: [OMPI users] MPI_AllReduce() deadlock on IB

2011-03-25 Thread Brock Palen
Running with rdmacm the problem does seam to resolve its self, The code is large and complicated, but the problem does appear to arise regularly when ran. Just FYI, can I collect extra information to help find a fix? Brock Palen www.umich.edu/~brockp Center for Advanced Computing bro...@umich.ed

Re: [OMPI users] MPI_AllReduce() deadlock on IB

2011-03-16 Thread Jeff Squyres
This could be related to https://svn.open-mpi.org/trac/ompi/ticket/2714 and/or https://svn.open-mpi.org/trac/ompi/ticket/2722. There isn't much info in the ticket, but we've been talking about it a bunch offline. IBM and Mellanox have had reports of the error, but haven't been able to reproduc

[OMPI users] MPI_AllReduce() deadlock on IB

2011-03-16 Thread Brock Palen
I have a user whos code when ran on ethernet performs fine. When ran on verbs based IB the code deadlocks in an MPI_AllReduce() call. We are using openmpi/1.4.3 with the intel compilers. I poked at the running code with padb and I get the following: 051525354...

Re: [OMPI users] MPI_ALLREDUCE bug with 1.5.2rc3r24441

2011-03-09 Thread Harald Anlauf
Jeff, it's funny because I do not see my problem with C (when using long long) but only with Fortran and INTEGER8. I have rewritten the testcase so that it uses MPI_REDUCE_LOCAL, which unfortunately does not link with openmpi-1.4.3. Apparently this is a new feature of openmpi-1.5. Here's the mo

Re: [OMPI users] MPI_ALLREDUCE bug with 1.5.2rc3r24441

2011-03-08 Thread Jeff Squyres
Try as I might, I cannot reproduce this error. :-( I only have the intel compiler version 11.x, though -- not 12. Can you change your test to use MPI_Reduce_local with INTEGER8 and see if the problem still occurs? (it probably will, but it is a significantly simpler code path to get down to t

Re: [OMPI users] MPI_ALLREDUCE bug with 1.5.2rc3r24441

2011-03-03 Thread Harald Anlauf
Please find attached the output of: configure make all make install ompi_info -all mpif90 -v mpiallreducetest.f90 ldd a.out ./a.out System: OpenSuse Linux 11.1 on Core2Duo, i686 Compiler is: Intel(R) Fortran Compiler XE for applications running on IA-32, Version 12.0.1.107 Build 20101116 (The p

Re: [OMPI users] MPI_ALLREDUCE bug with 1.5.2rc3r24441

2011-03-03 Thread Jeff Squyres
I am unable to reproduce your problem with the 1.5.2rc3 tarball...? Does your compiler support INTEGER8? Can you send the data requested here: http://www.open-mpi.org/community/help/ On Mar 1, 2011, at 4:16 PM, Harald Anlauf wrote: > Hi, > > there appears to be a regression in revision 1

[OMPI users] MPI_ALLREDUCE bug with 1.5.2rc3r24441

2011-03-01 Thread Harald Anlauf
Hi, there appears to be a regression in revision 1.5.2rc3r24441. The attached program crashes even with 1 PE with: Default real, digits: 4 24 Real kind,digits: 8 53 Integer kind, bits: 8 64 Default Integer :

Re: [OMPI users] MPI_Allreduce for INTEGER8?

2011-01-26 Thread Harald Anlauf
On 01/24/2011 11:28 PM, Harald Anlauf wrote: > Hi, > > MPI_Allreduce works for me with MPI_INTEGER8 for all OpenMPI > versions up to 1.4.3. However, with OpenMPI 1.5.1 I get a > failure at runtime: > > [proton:23642] *** An error occurred in MPI_Allreduce: the reduction > operation MPI_SUM is n

[OMPI users] MPI_Allreduce for MPI_INTEGER8 in 1.5.1?

2011-01-24 Thread Harald Anlauf
Hi, MPI_Allreduce works for me with MPI_INTEGER8 for all OpenMPI versions up to 1.4.3. However, with OpenMPI 1.5.1 I get a failure at runtime: [proton:23642] *** An error occurred in MPI_Allreduce: the reduction operation MPI_SUM is not defined on the MPI_INTEGER8 datatype [proton:23642] *** on

Re: [OMPI users] MPI_Allreduce on local machine

2010-08-16 Thread Jeff Squyres
On Aug 10, 2010, at 3:59 PM, Gus Correa wrote: > Thank you for opening a ticket and taking care of this. Sorry -- I missed your inline questions when I first read this mail... > > That being said, we didn't previously find any correctness > > issues with using an alignment of 1. > > Does it aff

Re: [OMPI users] MPI_Allreduce on local machine

2010-08-10 Thread Gus Correa
Hi Jeff Thank you for opening a ticket and taking care of this. Jeff Squyres wrote: On Jul 28, 2010, at 5:07 PM, Gus Correa wrote: Still, the alignment under Intel may or may not be right. And this may or may not explain the errors that Hugo has got. FYI, the ompi_info from my OpenMPI 1.3.2

Re: [OMPI users] MPI_Allreduce on local machine

2010-08-09 Thread Jeff Squyres
On Jul 28, 2010, at 5:07 PM, Gus Correa wrote: > Still, the alignment under Intel may or may not be right. > And this may or may not explain the errors that Hugo has got. > > FYI, the ompi_info from my OpenMPI 1.3.2 and 1.2.8 > report exactly the same as OpenMPI 1.4.2, namely > Fort dbl prec size

Re: [OMPI users] MPI_Allreduce on local machine

2010-08-09 Thread Jeff Squyres
On Jul 28, 2010, at 12:21 PM, Åke Sandgren wrote: > > Jeff: Is this correct? > > This is wrong, it should be 8 and alignement should be 8 even for intel. > And i also see exactly the same thing. Good catch! I just fixed this in https://svn.open-mpi.org/trac/ompi/changeset/23580 -- it looks li

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Hugo Gagnon
I also get 8 from "call MPI_Type_size(MPI_DOUBLE_PRECISION, size, mpierr)", but really I don't think this is the issue anymore. I mean I checked on my school cluster where OpenMPI has also been compiled with the intel64 compilers and "Fort dbl prec size:" also returns 4 but unlike on my Mac the cod

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Gus Correa
Hi All Martin Siegert wrote: On Wed, Jul 28, 2010 at 01:05:52PM -0700, Martin Siegert wrote: On Wed, Jul 28, 2010 at 11:19:43AM -0400, Gus Correa wrote: Hugo Gagnon wrote: Hi Gus, Ompi_info --all lists its info regarding fortran right after C. In my case: Fort real size: 4

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Martin Siegert
On Wed, Jul 28, 2010 at 01:05:52PM -0700, Martin Siegert wrote: > On Wed, Jul 28, 2010 at 11:19:43AM -0400, Gus Correa wrote: > > Hugo Gagnon wrote: > >> Hi Gus, > >> Ompi_info --all lists its info regarding fortran right after C. In my > >> case: > >> Fort real size: 4 > >> Fort

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Martin Siegert
On Wed, Jul 28, 2010 at 11:19:43AM -0400, Gus Correa wrote: > Hugo Gagnon wrote: >> Hi Gus, >> Ompi_info --all lists its info regarding fortran right after C. In my >> case: >> Fort real size: 4 >> Fort real4 size: 4 >> Fort real8 size: 8 >> Fort real16 size: 16

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Åke Sandgren
On Wed, 2010-07-28 at 11:48 -0400, Gus Correa wrote: > Hi Hugo, Jeff, list > > Hugo: I think David Zhang's suggestion was to use > MPI_REAL8 not MPI_REAL, instead of MPI_DOUBLE_PRECISION in your > MPI_Allreduce call. > > Still, to me it looks like OpenMPI is making double precision 4-byte > long

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Hugo Gagnon
Here they are. -- Hugo Gagnon On Wed, 28 Jul 2010 12:01 -0400, "Jeff Squyres" wrote: > On Jul 28, 2010, at 11:55 AM, Gus Correa wrote: > > > I surely can send you the logs, but they're big. > > Off the list perhaps? > > If they're still big when compressed, sure, send them to me off list. >

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Jeff Squyres
On Jul 28, 2010, at 11:55 AM, Gus Correa wrote: > I surely can send you the logs, but they're big. > Off the list perhaps? If they're still big when compressed, sure, send them to me off list. But I think I'd be more interested to see Hugo's logs. :-) -- Jeff Squyres jsquy...@cisco.com For co

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Gus Correa
Hi Jeff I surely can send you the logs, but they're big. Off the list perhaps? Thanks, Gus Jeff Squyres wrote: On Jul 28, 2010, at 11:19 AM, Gus Correa wrote: Ompi_info --all lists its info regarding fortran right after C. In my Ummm right... I should know that. I wrote ompi_info, aft

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Gus Correa
Hi Hugo, Jeff, list Hugo: I think David Zhang's suggestion was to use MPI_REAL8 not MPI_REAL, instead of MPI_DOUBLE_PRECISION in your MPI_Allreduce call. Still, to me it looks like OpenMPI is making double precision 4-byte long, which shorter than I expected it be (8 bytes), at least when look

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Jeff Squyres
On Jul 28, 2010, at 11:19 AM, Gus Correa wrote: > > Ompi_info --all lists its info regarding fortran right after C. In my Ummm right... I should know that. I wrote ompi_info, after all. :-) I ran "ompi_info -all | grep -i fortran" and didn't see the fortran info, and I forgot that I put

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Gus Correa
Hugo Gagnon wrote: Hi Gus, Ompi_info --all lists its info regarding fortran right after C. In my case: Fort real size: 4 Fort real4 size: 4 Fort real8 size: 8 Fort real16 size: 16 Fort dbl prec size: 4 Does it make any sense to you? Hi Hugo No, dbl pre

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Hugo Gagnon
I mean to write: call mpi_allreduce(inside, outside, 5,mpi_real, mpi_double_precision, mpi_comm_world, ierr) -- Hugo Gagnon On Wed, 28 Jul 2010 09:33 -0400, "Hugo Gagnon" wrote: > And how do I know how big my data buffer is? I ran MPI_TYPE_EXTENT of > And how do I know how big my data buffer

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Hugo Gagnon
I installed with: ./configure --prefix=/opt/openmpi CC=icc CXX=icpc F77=ifort FC=ifort make all install I would gladly give you a corefile but I have no idea on to produce one, I'm just an end user... -- Hugo Gagnon On Wed, 28 Jul 2010 08:57 -0400, "Jeff Squyres" wrote: > I don't have the i

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Hugo Gagnon
And how do I know how big my data buffer is? I ran MPI_TYPE_EXTENT of And how do I know how big my data buffer is? I ran MPI_TYPE_EXTENT of MPI_DOUBLE_PRECISION and the result was 8. So I changed my program to: 1 program test 2 3 use mpi 4 5 implicit none 6 7

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Jeff Squyres
I don't have the intel compilers on my Mac, but I'm unable to replicate this issue on Linux with the intel compilers v11.0. Can you get a corefile to see a backtrace where it died in Open MPI's allreduce? How exactly did you configure your Open MPI, and how exactly did you compile / run your sa

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Jeff Squyres
On Jul 27, 2010, at 4:19 PM, Gus Correa wrote: > Is there a simple way to check the number of bytes associated to each > MPI basic type of OpenMPI on a specific machine (or machine+compiler)? > > Something that would come out easily, say, from ompi_info? Not via ompi_info, but the MPI function M

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-28 Thread Jeff Squyres
On Jul 27, 2010, at 11:21 AM, Hugo Gagnon wrote: > I appreciate your replies but my question has to do with the function > MPI_Allreduce of OpenMPI built on a Mac OSX 10.6 with ifort (intel > fortran compiler). The implication I was going for was that if you were using MPI_DOUBLE_PRECISION with

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Terry Frankcombe
On Tue, 2010-07-27 at 16:19 -0400, Gus Correa wrote: > Hi Hugo, David, Jeff, Terry, Anton, list > > I suppose maybe we're guessing that somehow on Hugo's iMac > MPI_DOUBLE_PRECISION may not have as many bytes as dp = kind(1.d0), > hence the segmentation fault on MPI_Allreduce. > > Question: > >

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Hugo Gagnon
I did and it runs now, but the result is wrong: outside is still 1.d0, 2.d0, 3.d0, 4.d0, 5.d0 How can I make sure to compile OpenMPI so that datatypes such as mpi_double_precision behave as they "should"? Are there flags during the OpenMPI building process or something? Thanks, -- Hugo Gagnon

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Gus Correa
Hi Hugo, David, Jeff, Terry, Anton, list I suppose maybe we're guessing that somehow on Hugo's iMac MPI_DOUBLE_PRECISION may not have as many bytes as dp = kind(1.d0), hence the segmentation fault on MPI_Allreduce. Question: Is there a simple way to check the number of bytes associated to eac

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread David Zhang
Try mpi_real8 for the type in allreduce On 7/26/10, Hugo Gagnon wrote: > Hello, > > When I compile and run this code snippet: > > 1 program test > 2 > 3 use mpi > 4 > 5 implicit none > 6 > 7 integer :: ierr, nproc, myrank > 8 integer, parameter :: d

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Hugo Gagnon
I appreciate your replies but my question has to do with the function MPI_Allreduce of OpenMPI built on a Mac OSX 10.6 with ifort (intel fortran compiler). -- Hugo Gagnon On Tue, 27 Jul 2010 13:23 +0100, "Anton Shterenlikht" wrote: > On Tue, Jul 27, 2010 at 08:11:39AM -0400, Jeff Squyres wrot

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Anton Shterenlikht
On Tue, Jul 27, 2010 at 08:11:39AM -0400, Jeff Squyres wrote: > On Jul 26, 2010, at 11:06 PM, Hugo Gagnon wrote: > > > 8 integer, parameter :: dp = kind(1.d0) > > 9 real(kind=dp) :: inside(5), outside(5) > > I'm not a fortran expert -- is kind(1.d0) really double precision? A

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Terry Frankcombe
On Tue, 2010-07-27 at 08:11 -0400, Jeff Squyres wrote: > On Jul 26, 2010, at 11:06 PM, Hugo Gagnon wrote: > > > 8 integer, parameter :: dp = kind(1.d0) > > 9 real(kind=dp) :: inside(5), outside(5) > > I'm not a fortran expert -- is kind(1.d0) really double precision? Accordin

Re: [OMPI users] MPI_Allreduce on local machine

2010-07-27 Thread Jeff Squyres
On Jul 26, 2010, at 11:06 PM, Hugo Gagnon wrote: > 8 integer, parameter :: dp = kind(1.d0) > 9 real(kind=dp) :: inside(5), outside(5) I'm not a fortran expert -- is kind(1.d0) really double precision? According to http://gcc.gnu.org/onlinedocs/gcc-3.4.6/g77/Kind-Notation.htm

[OMPI users] MPI_Allreduce on local machine

2010-07-26 Thread Hugo Gagnon
Hello, When I compile and run this code snippet: 1 program test 2 3 use mpi 4 5 implicit none 6 7 integer :: ierr, nproc, myrank 8 integer, parameter :: dp = kind(1.d0) 9 real(kind=dp) :: inside(5), outside(5) 10 11 call mpi_

Re: [OMPI users] MPI_Allreduce()

2008-03-13 Thread Brock Palen
This is good information for me! For my users though its over the top. I was looking for simple reasons why, I think I have that now though. Thanks! Brock Palen Center for Advanced Computing bro...@umich.edu (734)936-1985 On Mar 13, 2008, at 11:16 AM, George Bosilca wrote: Collective co

Re: [OMPI users] MPI_Allreduce()

2008-03-13 Thread George Bosilca
Collective communication was a hot topic for the last [at least one] decade, and it is still today. Just minimizing the number of messages is not generally the best approach. The collectives are sensitive to the network characteristics and to the amount of data in a very complex way. The be

Re: [OMPI users] MPI_Allreduce()

2008-03-13 Thread Lawrence Stewart
Brock Palen wrote: Yeah, I know what you mean about if you have to use a 'all to all' use MPI_Alltoall() don't roll your own. So on paper, alltoall at first glance appears to be: n*(n-1) -> n^2- n -> n^2 (for large n). Allreduce appears to be simplest, n point to points followed by a

Re: [OMPI users] MPI_Allreduce()

2008-03-13 Thread Ashley Pittman
On Wed, 2008-03-12 at 18:05 -0400, Aurélien Bouteiller wrote: > If you can avoid them it is better to avoid them. However it is always > better to use a MPI_Alltoall than coding your own all to all with > point to point, and in some algorithms you *need* to make a all to all > communication.

Re: [OMPI users] MPI_Allreduce()

2008-03-13 Thread Brock Palen
Yeah, I know what you mean about if you have to use a 'all to all' use MPI_Alltoall() don't roll your own. So on paper, alltoall at first glance appears to be: n*(n-1) -> n^2- n -> n^2 (for large n). Allreduce appears to be simplest, n point to points followed by a bcast(). Which can

Re: [OMPI users] MPI_Allreduce()

2008-03-12 Thread Aurélien Bouteiller
If you can avoid them it is better to avoid them. However it is always better to use a MPI_Alltoall than coding your own all to all with point to point, and in some algorithms you *need* to make a all to all communication. What you should understand by "avoid all to all" is not avoid MPI_al

[OMPI users] MPI_Allreduce()

2008-03-12 Thread Brock Palen
I have always been told that calls like MPI_Barrior() MPI_Allreduce() and MPI_Alltoall() should be avoided. I understand MPI_Alltoall() as it goes n*(n-1) sends and thus grows very very quickly. MPI_Barrior() is very latency sensitive and generally is not needed in most cases I have seen

Re: [OMPI users] MPI_AllReduce design for shared-memory.

2007-08-14 Thread Jeff Squyres
The primary person you need to talk to is turning in her dissertation within the next few days. So I think she's kinda busy at the moment... :-) Sorry for the delay -- I'll take a shot at answers below... On Aug 14, 2007, at 4:39 PM, smai...@ksu.edu wrote: Can anyone help on this? -Tha

Re: [OMPI users] MPI_AllReduce design for shared-memory.

2007-08-14 Thread smairal
Thanks, I understand what you are saying. But my query is regarding the design of MPI_AllReduce for shared-memory systems. I mean is there any different logic/design of MPI_AllReduce when OpenMPI is used on shared-memory systems? The standard MPI_AllReduce says, 1. Each MPI process sends its value

Re: [OMPI users] MPI_AllReduce design for shared-memory.

2007-08-14 Thread smairal
Can anyone help on this? -Thanks, Sarang. Quoting smai...@ksu.edu: > Hi, > I am doing a research on parallel techniques for shared-memory > systems(NUMA). I understand that OpenMPI is intelligent to utilize > shared-memory system and it uses processor-affinity. Is the OpenMPI > design of MPI_All

[OMPI users] MPI_AllReduce design for shared-memory.

2007-08-10 Thread smairal
Hi, I am doing a research on parallel techniques for shared-memory systems(NUMA). I understand that OpenMPI is intelligent to utilize shared-memory system and it uses processor-affinity. Is the OpenMPI design of MPI_AllReduce "same" for shared-memory (NUMA) as well as distributed system? Can someon

Re: [OMPI users] MPI_Allreduce.3: wrong description for use of MPI_IN_PLACE

2007-01-17 Thread Jeff Squyres
You are absolutely correct, sir! Thanks for noticing -- we'll get that fixed up. On Jan 15, 2007, at 1:44 PM, Bert Wesarg wrote: Hello, I think the last sentence for the use of MPI_IN_PLACE in the new manual page is wrong: Use the variable MPI_IN_PLACE as the value of both sendbuf and

[OMPI users] MPI_Allreduce.3: wrong description for use of MPI_IN_PLACE

2007-01-15 Thread Bert Wesarg
Hello, I think the last sentence for the use of MPI_IN_PLACE in the new manual page is wrong: > Use the variable MPI_IN_PLACE as the value of both sendbuf and recvbuf. This is the end of line 110 in file https://svn.open-mpi.org/trac/ompi/browser/trunk/ompi/mpi/man/man3/MPI_Allreduce.3 Beside t

Re: [OMPI users] MPI_Allreduce error in 1.0.1 and 1.0.2rc1

2006-04-09 Thread john casu
apologies. -john. > > > -Original Message- > > From: users-boun...@open-mpi.org > > [mailto:users-boun...@open-mpi.org] On Behalf Of john casu > > Sent: Thursday, April 06, 2006 6:07 PM > > To: Open MPI Users > > Subject: Re: [OMPI users] MPI_Allr

Re: [OMPI users] MPI_Allreduce error in 1.0.1 and 1.0.2rc1

2006-04-08 Thread Jeff Squyres (jsquyres)
small program? > -Original Message- > From: users-boun...@open-mpi.org > [mailto:users-boun...@open-mpi.org] On Behalf Of john casu > Sent: Thursday, April 06, 2006 6:07 PM > To: Open MPI Users > Subject: Re: [OMPI users] MPI_Allreduce error in 1.0.1 and 1.0.2rc1 >

Re: [OMPI users] MPI_Allreduce error in 1.0.1 and 1.0.2rc1

2006-04-06 Thread john casu
On Thu, 2006-04-06 at 15:48 -0400, George Bosilca wrote: > The error state that your trying to use an invalid operation. MPI > define which operation can be applied on which predefined data-types. > Do you know which operation is used there ? And which predefined data- > type ? > please forg

Re: [OMPI users] MPI_Allreduce error in 1.0.1 and 1.0.2rc1

2006-04-06 Thread George Bosilca
The error state that your trying to use an invalid operation. MPI define which operation can be applied on which predefined data-types. Do you know which operation is used there ? And which predefined data- type ? Thanks, george. On Apr 6, 2006, at 2:41 PM, john casu wrote: I'm tryi

[OMPI users] MPI_Allreduce error in 1.0.1 and 1.0.2rc1

2006-04-06 Thread john casu
I'm trying to work with the sppm code form LLNL: http://www.llnl.gov/asci_benchmarks/asci/limited/ppm/asci_sppm.html I built openmpi and sppm on an 8-way shared memory Linux box. The error I get is: [ty20:07732] *** An error occurred in MPI_Allreduce [ty20:07732] *** on communicator MPI_COMM_WOR