Jeff,<br><br>Thank you for your reply! Although the MPI standard does not require it, stdin/stdout and passing data through pipes are traditional conveniences in Unix. I'd like MPICH2 improve on these besides performance. So, at present it seems I have to generate temporary files before using my data.<br>
<br>--<br>Yuheng<br><br><div class="gmail_quote">2012/2/28 Jeff Hammond <span dir="ltr"><<a href="mailto:jhammond@alcf.anl.gov">jhammond@alcf.anl.gov</a>></span><br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
The MPI standard does not even require stdin to be supported, so it is<br>
entirely reasonable for an implementation to support it only up to<br>
some reasonable finite value. If you were to run "cat /dev/random |<br>
mpiexec.gforker -n 2 ./test" that program would never return either.<br>
<br>
Since you are intending to use C++, why don't you modify your code to<br>
read from an istream associated with a proper input file rather than<br>
std::cin? The source changes should be essentially trivial.<br>
<br>
Jeff<br>
<div><div class="h5"><br>
On Tue, Feb 28, 2012 at 1:15 AM, Yuheng Xie <<a href="mailto:thinelephant@gmail.com">thinelephant@gmail.com</a>> wrote:<br>
> Hi,<br>
><br>
> I started using MPICH2 recently and found a problem about reading large file<br>
> (>64KB) from stdin. My program hanged up on the line MPI_Init(&argc,<br>
> &argv);. Could anyone help me? Thanks a lot.<br>
><br>
> My program: test.cpp<br>
> #include <mpi.h><br>
><br>
> int main(int argc, char **argv)<br>
> {<br>
> MPI_Init(&argc, &argv);<br>
> MPI_Finalize();<br>
><br>
> return 0;<br>
> }<br>
><br>
> Compile and run:<br>
> mpicxx test.cpp -o test<br>
> cat test.txt | mpiexec.gforker -n 2 ./test # This is OK<br>
> cat test.txt | mpiexec.hydra -n 2 ./test # When test.txt is larger than<br>
> 65536 bytes, this won't return.<br>
><br>
> The MPICH2 was installed with following commands:<br>
> ./configure --prefix=/usr/local --enable-cxx<br>
> --enable-fast=O3,nochkmsg,notiming,ndebug --with-pm=hydra:mpd:gforker<br>
> --enable-smpcoll<br>
> make<br>
> sudo make install<br>
><br>
><br>
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<span class="HOEnZb"><font color="#888888"><br>
<br>
<br>
--<br>
Jeff Hammond<br>
Argonne Leadership Computing Facility<br>
University of Chicago Computation Institute<br>
<a href="mailto:jhammond@alcf.anl.gov">jhammond@alcf.anl.gov</a> / (630) 252-5381<br>
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