mirror of git://gcc.gnu.org/git/gcc.git
63 lines
1.7 KiB
C
63 lines
1.7 KiB
C
/* { dg-do run } */
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/* { dg-set-target-env-var OMP_MAX_TASK_PRIORITY "10" } */
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/* This test verifies that the "priority" clause of omp task works as
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advertised.
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Testing the OpenMP task scheduler is a bit tricky, especially when
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trying to determine what ran first (without explicitly calling
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time() and/or synchronizing between threads). What we do here is
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run in single threaded mode which guarantees that we won't run into
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data races while accessing the "prio" array.
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We give each task a priority from 0..63, while setting
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OMP_MAX_TASK_PRIORITY to 10, which basically gives us 10 lower
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priority tasks, and the rest scheduled to run earlier. We verify
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that the priority < 10 tasks run last. */
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#include <omp.h>
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#include <stdlib.h>
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#define N 64
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int main()
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{
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int tsknum=0, prio[N];
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int max_priority = omp_get_max_task_priority ();
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int saved_tsknum = -1;
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int i;
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#pragma omp parallel num_threads(1)
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#pragma omp single private (i)
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{
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for (i = 0; i < N; i++)
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#pragma omp task priority(i ^ 1)
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{
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int t;
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#pragma omp atomic capture seq_cst
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t = tsknum++;
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prio[t] = i ^ 1;
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}
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#pragma omp atomic read seq_cst
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saved_tsknum = tsknum;
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}
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/* If any of the tasks have run before all tasks were created, don't
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make any assumption on the task order. Otherwise, we should have
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tasks with >= max_priority scheduled first in arbitrary order,
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followed by the rest of tasks in decreasing priority order, as
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there is only one thread that can schedule them. */
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if (saved_tsknum == 0)
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{
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for (i = 0; i < N; i++)
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if (i < N - max_priority)
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{
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if (prio[i] < max_priority)
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abort ();
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}
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else if (i != N - prio[i] - 1)
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abort ();
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}
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return 0;
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}
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