Hi Durga,
Sorry for the late reply and thanks for reporting that issue. As Rayson
mentioned, CUDA is intrinsically C++ and indeed uses the host C++
compiler. Hence linking MPI + CUDA code may need to use mpic++.
It happens to work with mpicc on various platforms where the libstdc++
is linked anyway but in your case it wasn't. We fixed the Makefile on
github to use mpic++ as linker.
Sylvain
On 03/20/2016 07:37 PM, dpchoudh . wrote:
I'd tend to agree with Gilles. I have written CUDA programs in pure C
(i.e. neither involving MPI nor C++) and a pure C based tool chain
builds the code successfully. So I don't see why CUDA should be
intrinsically C++.
From the Makefile (that I had attached in my previous mail) the only
CUDA library being linked against is this:
/usr/local/cuda/lib64/libcudart.so
and ldd on that shows this:
[durga@smallMPI lib64]$ ldd libcudart.so
linux-vdso.so.1 => (0x00007ffe1e7f1000)
libc.so.6 => /lib64/libc.so.6 (0x00007ff7e4493000)
libdl.so.2 => /lib64/libdl.so.2 (0x00007ff7e428f000)
libpthread.so.0 => /lib64/libpthread.so.0 (0x00007ff7e4072000)
librt.so.1 => /lib64/librt.so.1 (0x00007ff7e3e6a000)
/lib64/ld-linux-x86-64.so.2 (0x00007ff7e4af3000)
I don't see any C++ dependency here either.
And finally, I don't think there is any version issue. This is a clean
CUDA 7.5 install directly from NVIDIA CUDA repo (for Redhat) and all
provided examples run fine with this installation.
I believe there are NVIDIA employees in this list; hopefully one of
them will clarify.
Thanks
Durga
Life is complex. It has real and imaginary parts.
On Sun, Mar 20, 2016 at 10:23 PM, Gilles Gouaillardet
<gilles.gouaillar...@gmail.com <mailto:gilles.gouaillar...@gmail.com>>
wrote:
I am a bit puzzled...
if only cuda uses the c++ std libraries, then it should depend on them
(ldd libcudaxyz.so can be used to confirm that)
and then linking with cuda lib should pull the c++ libs
could there be a version issue ?
e.g. the missing symbol is not provided by the version of the c++
lib that is pulled.
that might occur if you are using cuda built for distro X on distro Y
could you please double check this ?
if everything should work, then i recommend you report this to nvidia
Cheers,
Gilles
On Monday, March 21, 2016, Damien Hocking <dam...@0x544745.com
<mailto:dam...@0x544745.com>> wrote:
Durga,
The Cuda libraries use the C++ std libraries. That's the
std::ios_base errors.. You need the C++ linker to bring those in.
Damien
On March 20, 2016 9:15:47 AM "dpchoudh ." <dpcho...@gmail.com>
wrote:
Hello all
I downloaded some code samples from here:
https://github.com/parallel-forall/code-samples/
and tried to build the subdirectory
posts/cuda-aware-mpi-example/src
in my CentOS 7 machine.
I had to make several changes to the Makefile before it would
build. The modified Makefile is attached (the make targets I
am talking about are the 3rd and 4th from the bottom). Most
of the modifications can be explained as possible platform
specific variations (such as path differences betwen Ubuntu
and CentOS), except the following:
I had to use a C++ linker (mpic++) to link in the object
files that were produced with C host compiler (mpicc) and
CUDA compiler (nvcc). If I did not do this, (i.e. I stuck to
mpicc for linking), I got the following link error:
mpicc -L/usr/local/cuda/lib64 -lcudart -lm -o
../bin/jacobi_cuda_normal_mpi jacobi.o input.o host.o
device.o cuda_normal_mpi.o
device.o: In function
`__static_initialization_and_destruction_0(int, int)':
tmpxft_00004651_00000000-4_Device.cudafe1.cpp:(.text+0xd1e):
undefined reference to `std::ios_base::Init::Init()'
tmpxft_00004651_00000000-4_Device.cudafe1.cpp:(.text+0xd2d):
undefined reference to `std::ios_base::Init::~Init()'
collect2: error: ld returned 1 exit status
Can someone please explain why would I need a C++ linker for
object files that were generated using C compiler? Note that
if I use mpic++ both for compiling and linking, there are no
errors either.
Thanks in advance
Durga
Life is complex. It has real and imaginary parts.
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