[llvm-dev] clang only spawns one thread

[zhi chen via llvm-dev]

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>