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mem-ruby: fix sharer update for stale WriteCleanFull

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Initiate_CopyBack_Stale removes the requestor from the sharer list.
However, if CBWrData_SC is the data response of stale WriteCleanFull,
the requestor should remain in the sharer list.
Thus, whether to send a Evict or not can be decided after the data
response arrives. For this, FinishCopyBack_Stale event was added as the
last event to handle Evict.

Change-Id: Ic3e3a1e4d74b24b9aa328b2ddfa817db44f24e4e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/58413
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Tiago Muck <tiago.muck@arm.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
This commit is contained in:
Daecheol You
2022-03-11 12:24:11 +09:00
parent 53009f9e69
commit eaf23bcd9f
3 changed files with 17 additions and 6 deletions
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16
src/mem/ruby/protocol/chi/CHI-cache-actions.sm
View File

@@ -904,17 +904,18 @@ action(Initiate_CopyBack_Stale, desc="") {
tbe.actions.pushNB(Event:SendCompDBIDRespStale);
tbe.actions.pushNB(Event:WriteFEPipe);
tbe.actions.push(Event:FinishCopyBack_Stale);
assert((tbe.dir_ownerExists == false) || (tbe.dir_owner != tbe.requestor));
}
action(Finish_CopyBack_Stale, desc="") {
// if it was the last known sharer and we don't have the data do the same
// the Initiate_Evict
if ((is_HN == false) && (tbe.dir_sharers.count() == 1) &&
if ((is_HN == false) && (tbe.dir_sharers.count() == 0) &&
tbe.dir_sharers.isElement(tbe.requestor) && (tbe.dataValid == false)) {
tbe.actions.push(Event:SendEvict);
}
tbe.dir_sharers.remove(tbe.requestor);
assert((tbe.dir_ownerExists == false) || (tbe.dir_owner != tbe.requestor));
}
action(Initiate_Evict, desc="") {
@@ -1756,7 +1757,10 @@ action(UpdateDirState_FromReqDataResp, desc="") {
} else if (in_msg.type == CHIDataType:CBWrData_SC) {
assert((tbe.dir_ownerExists == false) || (tbe.dir_owner != in_msg.responder));
tbe.dir_sharers.remove(in_msg.responder);
// Do not remove the responder in case of stale WriteCleanFull
if (tbe.reqType != CHIRequestType:WriteCleanFull) {
tbe.dir_sharers.remove(in_msg.responder);
}
} else if (in_msg.type == CHIDataType:CBWrData_SD_PD) {
assert(tbe.dir_ownerExists && (tbe.dir_ownerIsExcl == false) && (tbe.dir_owner == in_msg.responder));

6
src/mem/ruby/protocol/chi/CHI-cache-transitions.sm
View File

@@ -1043,6 +1043,12 @@ transition(BUSY_BLKD, FinishCleanUnique) {
ProcessNextState_ClearPending;
}
transition(BUSY_BLKD, FinishCopyBack_Stale) {
Pop_TriggerQueue;
Finish_CopyBack_Stale;
ProcessNextState_ClearPending;
}
transition(BUSY_BLKD, CheckUpgrade_FromStore) {
Pop_TriggerQueue;
Callback_Miss; // note: Callback happens only if tbe.dataValid

1
src/mem/ruby/protocol/chi/CHI-cache.sm
View File

@@ -504,6 +504,7 @@ machine(MachineType:Cache, "Cache coherency protocol") :
TX_Data, desc="Transmit pending data messages";
MaintainCoherence, desc="Queues a WriteBack or Evict before droping the only valid copy of the block";
FinishCleanUnique, desc="Sends acks and perform any writeback after a CleanUnique";
FinishCopyBack_Stale, desc="Check if a Evict needs to be sent";
ActionStalledOnHazard, desc="Stall a trigger action because until finish handling snoop hazard";
// This is triggered once a transaction doesn't have