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authorKorey Sewell <ksewell@umich.edu>2011-02-04 00:08:13 -0500
committerKorey Sewell <ksewell@umich.edu>2011-02-04 00:08:13 -0500
commit7f937e11e2779628002d063a368ee3101a32471d (patch)
tree4abcb47af12755b24520a51c29650ce16a13cd94 /src
parent091a3e6cc0f089b6ba6877c8127ebd2ebf8e7c21 (diff)
downloadgem5-7f937e11e2779628002d063a368ee3101a32471d.tar.xz
inorder: activity tracking bug
Previous code was marking CPU activity on almost every cycle due to a bug in tracking the status of pipeline stages. This disables the CPU from sleeping on long latency stalls and increases simulation time
Diffstat (limited to 'src')
-rw-r--r--src/cpu/inorder/first_stage.cc9
-rw-r--r--src/cpu/inorder/pipeline_stage.cc38
2 files changed, 32 insertions, 15 deletions
diff --git a/src/cpu/inorder/first_stage.cc b/src/cpu/inorder/first_stage.cc
index ae458c604..424d6b6a4 100644
--- a/src/cpu/inorder/first_stage.cc
+++ b/src/cpu/inorder/first_stage.cc
@@ -126,8 +126,10 @@ FirstStage::processStage(bool &status_change)
if (tid >= 0) {
DPRINTF(InOrderStage, "Processing [tid:%i]\n",tid);
processThread(status_change, tid);
+ DPRINTF(InOrderStage, "Done Processing [tid:%i]\n",tid);
} else {
DPRINTF(InOrderStage, "No more threads to fetch from.\n");
+ break;
}
}
@@ -148,7 +150,7 @@ FirstStage::processInsts(ThreadID tid)
{
bool all_reqs_completed = true;
- for (int insts_fetched = 0;
+ for (int insts_fetched = instsProcessed;
insts_fetched < stageWidth && canSendInstToStage(1);
insts_fetched++) {
@@ -200,8 +202,11 @@ FirstStage::processInsts(ThreadID tid)
"list.\n", tid, inst->seqNum);
insts[tid].push(inst);
}
+ block(tid);
break;
} else if (!insts[tid].empty()){
+ DPRINTF(InOrderStage, "[tid:%u]: [sn:%u] Finished all "
+ "requests for this stage.\n", tid, inst->seqNum);
insts[tid].pop();
}
@@ -210,7 +215,7 @@ FirstStage::processInsts(ThreadID tid)
// Record that stage has written to the time buffer for activity
// tracking.
- if (toNextStageIndex) {
+ if (instsProcessed) {
wroteToTimeBuffer = true;
}
}
diff --git a/src/cpu/inorder/pipeline_stage.cc b/src/cpu/inorder/pipeline_stage.cc
index 2ac402fae..710af5332 100644
--- a/src/cpu/inorder/pipeline_stage.cc
+++ b/src/cpu/inorder/pipeline_stage.cc
@@ -281,15 +281,15 @@ PipelineStage::block(ThreadID tid)
// signalled fetch to unblock. In that case, there is no need to tell
// fetch to block.
if (stageStatus[tid] != Blocked) {
- // Set the status to Blocked.
- stageStatus[tid] = Blocked;
-
if (stageStatus[tid] != Unblocking) {
- if (prevStageValid)
- toPrevStages->stageBlock[stageNum][tid] = true;
wroteToTimeBuffer = true;
}
+ stageStatus[tid] = Blocked;
+
+ if (prevStageValid)
+ toPrevStages->stageBlock[stageNum][tid] = true;
+
return true;
}
@@ -304,12 +304,12 @@ PipelineStage::blockDueToBuffer(ThreadID tid)
"next stage.\n", tid);
if (stageStatus[tid] != Blocked) {
- // Set the status to Blocked.
- stageStatus[tid] = Blocked;
-
if (stageStatus[tid] != Unblocking) {
wroteToTimeBuffer = true;
}
+
+ // Set the status to Blocked.
+ stageStatus[tid] = Blocked;
}
}
@@ -595,18 +595,26 @@ PipelineStage::sortInsts()
{
if (prevStageValid) {
int insts_from_prev_stage = prevStage->size;
+ int insts_from_cur_stage = skidSize();
+ DPRINTF(InOrderStage, "%i insts available from stage buffer %i. Stage "
+ "currently has %i insts from last cycle.\n",
+ insts_from_prev_stage, prevStageQueue->id(),
+ insts_from_cur_stage);
- DPRINTF(InOrderStage, "%i insts available from stage buffer %i.\n",
- insts_from_prev_stage, prevStageQueue->id());
-
+ int inserted_insts = 0;
for (int i = 0; i < insts_from_prev_stage; ++i) {
+ if (inserted_insts + insts_from_cur_stage == stageWidth) {
+ DPRINTF(InOrderStage, "Stage %i has accepted all insts "
+ "possible for this tick.\n");
+ break;
+ }
if (prevStage->insts[i]->isSquashed()) {
DPRINTF(InOrderStage, "[tid:%i]: Ignoring squashed [sn:%i], "
"not inserting into stage buffer.\n",
prevStage->insts[i]->readTid(),
prevStage->insts[i]->seqNum);
-
+ prevStage->size--;
continue;
}
@@ -622,7 +630,11 @@ PipelineStage::sortInsts()
prevStage->insts[i] = cpu->dummyBufferInst;
+ prevStage->size--;
+
+ inserted_insts++;
}
+ assert(prevStage->size == 0);
}
}
@@ -937,7 +949,7 @@ PipelineStage::processInsts(ThreadID tid)
// Record that stage has written to the time buffer for activity
// tracking.
- if (toNextStageIndex) {
+ if (instsProcessed) {
wroteToTimeBuffer = true;
}
}