Hi,
I am using LLVM 3.6.1 to test the following code:
#include <omp.h>
#include <stdio.h>
#include <stdlib.h>
int main() {
int tid, nthreads;
#pragma omp parallel sections private(nthreads, tid)
{
#pragma omp section
{
tid = omp_get_thread_num();
printf("Hello, tid = %d\n ", tid);
}
#pragma omp section
{
tid = omp_get_thread_num();
printf("Hello, tid = %d\n ", tid);
}
}
if (tid == 0) {
nthreads = omp_get_num_threads();
printf("number of threads = %d \n", nthreads);
}
return 0;
}
I used the following command:
clang -fopenmp -I/path/to/omp.h -L/path/to/libomp.so test.c -o test
I only get one thread when I run test, for example it yields:
Hello, tid = 0
Hello, tid = 0
number of threads = 1
However, I can get different thread id if I compile the code using gcc. Any
idea about what's wrong here?
I found a similarly problem in the following link:
http://stackoverflow.com/questions/31663996/clang-llvm-openmp-program-not-spawning-threads/31673394#31673394
But I don't know where should I add -fopenmp=libomp. Any help will be
appreciated. Thanks.
Zhi
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.llvm.org/pipermail/llvm-dev/attachments/20151202/ea22865c/attachment.html>
Hi Zhi, take a look at this thread: http://stackoverflow.com/questions/33357029/using-openmp-with-clang Regards, Jakub On 2 December 2015 at 22:52, zhi chen via llvm-dev <llvm-dev at lists.llvm.org> wrote:> Hi, > > I am using LLVM 3.6.1 to test the following code: > > #include <omp.h> > #include <stdio.h> > #include <stdlib.h> > > int main() { > > int tid, nthreads; > #pragma omp parallel sections private(nthreads, tid) > { > #pragma omp section > { > tid = omp_get_thread_num(); > printf("Hello, tid = %d\n ", tid); > } > > #pragma omp section > { > tid = omp_get_thread_num(); > printf("Hello, tid = %d\n ", tid); > } > } > if (tid == 0) { > nthreads = omp_get_num_threads(); > printf("number of threads = %d \n", nthreads); > } > > return 0; > } > > I used the following command: > clang -fopenmp -I/path/to/omp.h -L/path/to/libomp.so test.c -o test > > I only get one thread when I run test, for example it yields: > Hello, tid = 0 > Hello, tid = 0 > number of threads = 1 > > However, I can get different thread id if I compile the code using gcc. > Any idea about what's wrong here? > > I found a similarly problem in the following link: > > http://stackoverflow.com/questions/31663996/clang-llvm-openmp-program-not-spawning-threads/31673394#31673394 > > But I don't know where should I add -fopenmp=libomp. Any help will be > appreciated. Thanks. > > Zhi > > _______________________________________________ > LLVM Developers mailing list > llvm-dev at lists.llvm.org > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev > >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20151202/49180830/attachment.html>
Hi Jakub, Thanks. I upgraded my LLVM and everything worked. Best, Zhi On Wed, Dec 2, 2015 at 2:26 PM, Jakub Kuderski <kubakuderski+llvm at gmail.com> wrote:> Hi Zhi, > > take a look at this thread: > http://stackoverflow.com/questions/33357029/using-openmp-with-clang > > Regards, > Jakub > > On 2 December 2015 at 22:52, zhi chen via llvm-dev < > llvm-dev at lists.llvm.org> wrote: > >> Hi, >> >> I am using LLVM 3.6.1 to test the following code: >> >> #include <omp.h> >> #include <stdio.h> >> #include <stdlib.h> >> >> int main() { >> >> int tid, nthreads; >> #pragma omp parallel sections private(nthreads, tid) >> { >> #pragma omp section >> { >> tid = omp_get_thread_num(); >> printf("Hello, tid = %d\n ", tid); >> } >> >> #pragma omp section >> { >> tid = omp_get_thread_num(); >> printf("Hello, tid = %d\n ", tid); >> } >> } >> if (tid == 0) { >> nthreads = omp_get_num_threads(); >> printf("number of threads = %d \n", nthreads); >> } >> >> return 0; >> } >> >> I used the following command: >> clang -fopenmp -I/path/to/omp.h -L/path/to/libomp.so test.c -o test >> >> I only get one thread when I run test, for example it yields: >> Hello, tid = 0 >> Hello, tid = 0 >> number of threads = 1 >> >> However, I can get different thread id if I compile the code using gcc. >> Any idea about what's wrong here? >> >> I found a similarly problem in the following link: >> >> http://stackoverflow.com/questions/31663996/clang-llvm-openmp-program-not-spawning-threads/31673394#31673394 >> >> But I don't know where should I add -fopenmp=libomp. Any help will be >> appreciated. Thanks. >> >> Zhi >> >> _______________________________________________ >> LLVM Developers mailing list >> llvm-dev at lists.llvm.org >> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev >> >> >-------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20151202/1b204588/attachment.html>