Improvements to machine_hierarchy code for re-sizing
These changes include:
1) Machine hierarchy now uses the base_num_threads field to indicate the
maximum number of threads the current hierarchy can handle without a resize.
2) In __kmp_get_hierarchy, we need to get depth after any potential resize
is done.
3) Cleanup of hierarchy resize code to support 1 above.
Differential Revision: http://reviews.llvm.org/D14455
llvm-svn: 252475
diff --git a/openmp/runtime/src/kmp_affinity.h b/openmp/runtime/src/kmp_affinity.h
index 0385307..24a7d40 100644
--- a/openmp/runtime/src/kmp_affinity.h
+++ b/openmp/runtime/src/kmp_affinity.h
@@ -237,54 +237,57 @@
void resize(kmp_uint32 nproc)
{
kmp_int8 bool_result = KMP_COMPARE_AND_STORE_ACQ8(&resizing, 0, 1);
- if (bool_result == 0) { // Someone else is resizing
- while (TCR_1(resizing) != 0) KMP_CPU_PAUSE();
- return;
+ while (bool_result == 0) { // someone else is trying to resize
+ KMP_CPU_PAUSE();
+ if (nproc <= base_num_threads) // happy with other thread's resize
+ return;
+ else // try to resize
+ bool_result = KMP_COMPARE_AND_STORE_ACQ8(&resizing, 0, 1);
}
KMP_DEBUG_ASSERT(bool_result!=0);
- KMP_DEBUG_ASSERT(nproc > base_num_threads);
+ if (nproc <= base_num_threads) return; // happy with other thread's resize
// Calculate new maxLevels
kmp_uint32 old_sz = skipPerLevel[depth-1];
kmp_uint32 incs = 0, old_maxLevels = maxLevels;
- // First see if old maxLevels is enough to contain new size
+ // First see if old maxLevels is enough to contain new size
for (kmp_uint32 i=depth; i<maxLevels && nproc>old_sz; ++i) {
skipPerLevel[i] = 2*skipPerLevel[i-1];
+ numPerLevel[i-1] *= 2;
old_sz *= 2;
depth++;
}
- if (nproc <= old_sz) // enough space already
- return;
- // Not enough space, need to expand hierarchy
- while (nproc > old_sz) {
- old_sz *=2;
- incs++;
- depth++;
- }
- maxLevels += incs;
+ if (nproc > old_sz) { // Not enough space, need to expand hierarchy
+ while (nproc > old_sz) {
+ old_sz *=2;
+ incs++;
+ depth++;
+ }
+ maxLevels += incs;
- // Resize arrays
- kmp_uint32 *old_numPerLevel = numPerLevel;
- kmp_uint32 *old_skipPerLevel = skipPerLevel;
- numPerLevel = skipPerLevel = NULL;
- numPerLevel = (kmp_uint32 *)__kmp_allocate(maxLevels*2*sizeof(kmp_uint32));
- skipPerLevel = &(numPerLevel[maxLevels]);
+ // Resize arrays
+ kmp_uint32 *old_numPerLevel = numPerLevel;
+ kmp_uint32 *old_skipPerLevel = skipPerLevel;
+ numPerLevel = skipPerLevel = NULL;
+ numPerLevel = (kmp_uint32 *)__kmp_allocate(maxLevels*2*sizeof(kmp_uint32));
+ skipPerLevel = &(numPerLevel[maxLevels]);
- // Copy old elements from old arrays
- for (kmp_uint32 i=0; i<old_maxLevels; ++i) { // init numPerLevel[*] to 1 item per level
- numPerLevel[i] = old_numPerLevel[i];
- skipPerLevel[i] = old_skipPerLevel[i];
+ // Copy old elements from old arrays
+ for (kmp_uint32 i=0; i<old_maxLevels; ++i) { // init numPerLevel[*] to 1 item per level
+ numPerLevel[i] = old_numPerLevel[i];
+ skipPerLevel[i] = old_skipPerLevel[i];
+ }
+
+ // Init new elements in arrays to 1
+ for (kmp_uint32 i=old_maxLevels; i<maxLevels; ++i) { // init numPerLevel[*] to 1 item per level
+ numPerLevel[i] = 1;
+ skipPerLevel[i] = 1;
+ }
+
+ // Free old arrays
+ __kmp_free(old_numPerLevel);
}
- // Init new elements in arrays to 1
- for (kmp_uint32 i=old_maxLevels; i<maxLevels; ++i) { // init numPerLevel[*] to 1 item per level
- numPerLevel[i] = 1;
- skipPerLevel[i] = 1;
- }
-
- // Free old arrays
- __kmp_free(old_numPerLevel);
-
// Fill in oversubscription levels of hierarchy
for (kmp_uint32 i=old_maxLevels; i<maxLevels; ++i)
skipPerLevel[i] = 2*skipPerLevel[i-1];