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| author | Tuan Ta <qtt2@cornell.edu> | 2018-04-02 16:22:16 -0400 |
|---|---|---|
| committer | Tuan Ta <qtt2@cornell.edu> | 2019-02-08 15:25:30 +0000 |
| commit | e437086341712f1435db655b3527ea29b3311f4e (patch) | |
| tree | 120fba453d75521ce3535ef93229fd8c6b1409ad | |
| parent | 6a6668bbc4b038b98eb3ee64ffb034719316afd9 (diff) | |
| download | gem5-e437086341712f1435db655b3527ea29b3311f4e.tar.xz | |
cpu: fix how branching is handled when a thread is suspended in MinorCPU
When a thread is suspended, all instructions after the suspension need
to be discarded since the thread will take a different execution stream
when it wakes up.
To do that, in MinorCPU, whenever a thread gets suspended, we change the
current execution stream by updating the current branch with
BranchData::SuspendThread reason.
Change-Id: I7cdcda22c1cf6e8ac8db8800b7d9ec052433fdf3
Reviewed-on: https://gem5-review.googlesource.com/c/9626
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Giacomo Gabrielli <giacomo.gabrielli@gmail.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
| -rw-r--r-- | src/cpu/minor/execute.cc | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/src/cpu/minor/execute.cc b/src/cpu/minor/execute.cc index d7cb475c6..234a233c2 100644 --- a/src/cpu/minor/execute.cc +++ b/src/cpu/minor/execute.cc @@ -248,7 +248,14 @@ Execute::tryToBranch(MinorDynInstPtr inst, Fault fault, BranchData &branch) pc_before, target); } - if (inst->predictedTaken && !force_branch) { + if (thread->status() == ThreadContext::Suspended) { + /* Thread got suspended */ + DPRINTF(Branch, "Thread got suspended: branch from 0x%x to 0x%x " + "inst: %s\n", + inst->pc.instAddr(), target.instAddr(), *inst); + + reason = BranchData::SuspendThread; + } else if (inst->predictedTaken && !force_branch) { /* Predicted to branch */ if (!must_branch) { /* No branch was taken, change stream to get us back to the @@ -1054,8 +1061,7 @@ Execute::commit(ThreadID thread_id, bool only_commit_microops, bool discard, !branch.isStreamChange() && /* No real branch */ fault == NoFault && /* No faults */ completed_inst && /* Still finding instructions to execute */ - num_insts_committed != commitLimit && /* Not reached commit limit */ - cpu.getContext(thread_id)->status() != ThreadContext::Suspended + num_insts_committed != commitLimit /* Not reached commit limit */ ) { if (only_commit_microops) { |