PAPI_unregister_thread(3)

1PAPI_register_thread(3)              PAPI              PAPI_register_thread(3)
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NAME

6       PAPI_register_thread,  PAPI_unregister_thread  -  Inform PAPI of thread
7       status
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SYNOPSIS

11       #include <papi.h>
12       int PAPI_register_thread (void);
13       int PAPI_unregister_thread (void);
14       Fortran Interface
15       #include fpapi.h
16       PAPIF_register_thread(C_INT check)
17       PAPIF_unregister_thread(C_INT check)
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DESCRIPTION

21       PAPI_register_thread should be called when the user wants to force PAPI
22       to  initialize  a thread that PAPI has not seen before. Usually this is
23       not necessary as PAPI implicitly detects the thread when an eventset is
24       created  or  other  thread local PAPI functions are called. However, it
25       can be useful for debugging and performance enhancements  in  the  run-
26       time systems of performance tools.
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28       PAPI_unregister_thread should be called when the user wants to shutdown
29       a particular thread and free the associated thread ID. THIS  IS  IMPOR‐
30       TANT  IF YOUR THREAD LIBRARY REUSES THE SAME THREAD ID FOR A NEW KERNEL
31       LWP. OpenMP does this.  OpenMP parallel regions, if separated by a call
32       to omp_set_num_threads() will often kill off the underlying kernel LWPs
33       and   then   start   new   ones   for   the   next   region.   However,
34       omp_get_thread_id()  does  not  reflect this, as the thread IDs for the
35       new LWPs will be the same as the old LWPs. PAPI needs to know that  the
36       underlying  LWP  has changed so it can set up the counters for that new
37       thread. This is accomplished by calling this function.
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ARGUMENTS

41       None.
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RETURN VALUES

45       On success, this function returns PAPI_OK.  On error, a non-zero  error
46       code is returned.
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ERRORS

50       PAPI_ENOMEM
51              Space  could  not  be allocated to store the new thread informa‐
52              tion.
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54       PAPI_ESYS
55              A system or C library call failed inside  PAPI,  see  the  errno
56              variable.
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58       PAPI_ESBSTR
59              Hardware counters for this thread could not be initialized.
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EXAMPLES

63       None.
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