diff options
author | Mitch Hayenga <mitch.hayenga@arm.com> | 2016-07-21 17:19:16 +0100 |
---|---|---|
committer | Mitch Hayenga <mitch.hayenga@arm.com> | 2016-07-21 17:19:16 +0100 |
commit | 752f1c1fe9e74ebb0d373276b332b3242e589208 (patch) | |
tree | 66681f689812f3bba1b8c5f9b1cd301fe5490310 /src/cpu/minor/execute.cc | |
parent | ff4009ac005be0347015f8ba5a8e37a3aa930e69 (diff) | |
download | gem5-752f1c1fe9e74ebb0d373276b332b3242e589208.tar.xz |
cpu: Fix Minor SMT WFI/drain interaction issues
The behavior of WFI is to cause minor to cease evaluating
pipeline logic until an interrupt is observed, however
a user may wish to drain the system while a core is sleeping
due to a WFI. This patch makes WFI drain. If an actual
drain occurs during a WFI, the CPU is already drained and will
immediately be ready for swapping, checkpointing, etc. This
should not negatively impact performance as WFI instructions
are 'stream-changing' (treated like unpredicted branches), so
all remaining instructions are wrong-path and will be squashed
rapidly.
Change-Id: I63833d5acb53d8dde78f9f0c9611de0ece385e45
Diffstat (limited to 'src/cpu/minor/execute.cc')
-rw-r--r-- | src/cpu/minor/execute.cc | 20 |
1 files changed, 8 insertions, 12 deletions
diff --git a/src/cpu/minor/execute.cc b/src/cpu/minor/execute.cc index b13e0c020..f5f006733 100644 --- a/src/cpu/minor/execute.cc +++ b/src/cpu/minor/execute.cc @@ -559,10 +559,11 @@ Execute::issue(ThreadID thread_id) } else if (cpu.getContext(thread_id)->status() == ThreadContext::Suspended) { - DPRINTF(MinorExecute, "Not issuing inst: %s from suspended" + DPRINTF(MinorExecute, "Discarding inst: %s from suspended" " thread\n", *inst); - issued = false; + issued = true; + discarded = true; } else if (inst->id.streamSeqNum != thread.streamSeqNum) { DPRINTF(MinorExecute, "Discarding inst: %s as its stream" " state was unexpected, expected: %d\n", @@ -880,9 +881,8 @@ Execute::commitInst(MinorDynInstPtr inst, bool early_memory_issue, if (thread->status() == ThreadContext::Suspended && !isInterrupted(thread_id)) { - DPRINTF(MinorExecute, "Not committing inst from suspended thread" - " inst: %s\n", *inst); - completed_inst = false; + panic("We should never hit the case where we try to commit from a " + "suspended thread as the streamSeqNum should not match"); } else if (inst->isFault()) { ExecContext context(cpu, *cpu.threads[thread_id], *this, inst); @@ -1485,9 +1485,7 @@ Execute::evaluate() if (inst->isFault()) { can_issue_next = true; } else if (!inst->isBubble()) { - if (cpu.getContext(tid)->status() != ThreadContext::Suspended) { - next_issuable_insts.push_back(inst); - } + next_issuable_insts.push_back(inst); } } } @@ -1741,8 +1739,7 @@ Execute::getIssuingThread() } for (auto tid : priority_list) { - if (cpu.getContext(tid)->status() == ThreadContext::Active && - getInput(tid)) { + if (getInput(tid)) { issuePriority = tid; return tid; } @@ -1823,8 +1820,7 @@ Execute::isDrained() return false; for (ThreadID tid = 0; tid < cpu.numThreads; tid++) { - if (executeInfo[tid].drainState != DrainAllInsts || - !inputBuffer[tid].empty() || + if (!inputBuffer[tid].empty() || !executeInfo[tid].inFlightInsts->empty()) { return false; |