64-BitBrainstorm_2026/AMSS-NCKU
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skip redundant MPI ghost cell syncs for stages 0, 1 & 2

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BSSN 每个 RK4 时间步执行 4 次 MPI ghost zone 同步：
Stage 0（预测）结束后：Parallel::Sync(SynchList_pre)
Stage 1（校正 1）结束后：Parallel::Sync(SynchList_cor)
Stage 2（校正 2）结束后：Parallel::Sync(SynchList_cor)
Stage 3（校正 3）结束后：Parallel::Sync(SynchList_cor) ← 必要（为下一步提供 ghost）

bssnEM_class.C、Z4c_class.C 结构相同，一起修改了
This commit is contained in:
ianchb
2026-02-26 16:16:33 +08:00
parent 318b5254cc
commit 780f1c80d0
3 changed files with 60 additions and 105 deletions
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57
AMSS_NCKU_source/Z4c_class.C
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@@ -485,25 +485,7 @@ void Z4c_class::Step(int lev, int YN)
}
#endif
Parallel::Sync(GH->PatL[lev], SynchList_pre, Symmetry);
#ifdef WithShell
if (lev == 0)
{
clock_t prev_clock, curr_clock;
if (myrank == 0)
curr_clock = clock();
SH->Synch(SynchList_pre, Symmetry);
if (myrank == 0)
{
prev_clock = curr_clock;
curr_clock = clock();
cout << " Shell stuff synchronization used "
<< (double)(curr_clock - prev_clock) / ((double)CLOCKS_PER_SEC)
<< " seconds! " << endl;
}
}
#endif
// CA-RK4: skip post-prediction sync (redundant; ghost cells computable locally)
// for black hole position
if (BH_num > 0 && lev == GH->levels - 1)
@@ -868,25 +850,28 @@ void Z4c_class::Step(int lev, int YN)
}
#endif
Parallel::Sync(GH->PatL[lev], SynchList_cor, Symmetry);
// CA-RK4: only sync after last corrector (iter_count == 3); stages 1 & 2 are redundant
if (iter_count == 3) {
Parallel::Sync(GH->PatL[lev], SynchList_cor, Symmetry);
#ifdef WithShell
if (lev == 0)
{
clock_t prev_clock, curr_clock;
if (myrank == 0)
curr_clock = clock();
SH->Synch(SynchList_cor, Symmetry);
if (myrank == 0)
if (lev == 0)
{
prev_clock = curr_clock;
curr_clock = clock();
cout << " Shell stuff synchronization used "
<< (double)(curr_clock - prev_clock) / ((double)CLOCKS_PER_SEC)
<< " seconds! " << endl;
clock_t prev_clock, curr_clock;
if (myrank == 0)
curr_clock = clock();
SH->Synch(SynchList_cor, Symmetry);
if (myrank == 0)
{
prev_clock = curr_clock;
curr_clock = clock();
cout << " Shell stuff synchronization used "
<< (double)(curr_clock - prev_clock) / ((double)CLOCKS_PER_SEC)
<< " seconds! " << endl;
}
}
}
#endif
} // end CA-RK4 guard
// for black hole position
if (BH_num > 0 && lev == GH->levels - 1)
{
@@ -1558,7 +1543,7 @@ void Z4c_class::Step(int lev, int YN)
}
}
Parallel::Sync(GH->PatL[lev], SynchList_pre, Symmetry);
// CA-RK4: skip post-prediction MPI ghost sync (redundant; ghost cells computable locally)
if (lev == 0)
{
@@ -2120,7 +2105,9 @@ void Z4c_class::Step(int lev, int YN)
}
}
Parallel::Sync(GH->PatL[lev], SynchList_cor, Symmetry);
// CA-RK4: only MPI sync after last corrector (iter_count == 3); stages 1 & 2 are redundant
if (iter_count == 3)
Parallel::Sync(GH->PatL[lev], SynchList_cor, Symmetry);
if (lev == 0)
{