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Refactor arbiter assignment: fixup a bug caused by a missing conditio…
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…n in assigning new arbiter (#1683)
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@erwei-xilinx
erwei-xilinx committed Aug 13, 2024
1 parent 739ed99 commit ce528d4
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Showing 3 changed files with 85 additions and 35 deletions.
116 changes: 83 additions & 33 deletions lib/Dialect/AIE/Transforms/AIECreatePathFindFlows.cpp
100755 → 100644
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Original file line number Diff line number Diff line change
Expand Up @@ -390,6 +390,41 @@ void AIEPathfinderPass::runOnPacketFlow(DeviceOp device, OpBuilder &builder) {
int numMsels = 4;
int numArbiters = 6;

// Get arbiter id from amsel
auto getArbiterIDFromAmsel = [numArbiters](int amsel) {
return amsel % numArbiters;
};
// Get amsel from arbiter id and msel
auto getAmselFromArbiterIDAndMsel = [numArbiters](int arbiter, int msel) {
return arbiter + msel * numArbiters;
};
// Get a new unique amsel from masterAMSels on tile op. Prioritize on
// incrementing arbiter id, before incrementing msel
auto getNewUniqueAmsel = [&](DenseMap<std::pair<Operation *, int>,
SmallVector<Port, 4>>
masterAMSels,
Operation *tileOp) {
for (int i = 0; i < numMsels; i++)
for (int a = 0; a < numArbiters; a++)
if (!masterAMSels.count({tileOp, getAmselFromArbiterIDAndMsel(a, i)}))
return getAmselFromArbiterIDAndMsel(a, i);
tileOp->emitOpError("tile op has used up all arbiter-msel combinations");
return -1;
};
// Get a new unique amsel from masterAMSels on tile op with given arbiter id
auto getNewUniqueAmselPerArbiterID =
[&](DenseMap<std::pair<Operation *, int>, SmallVector<Port, 4>>
masterAMSels,
Operation *tileOp, int arbiter) {
for (int i = 0; i < numMsels; i++)
if (!masterAMSels.count(
{tileOp, getAmselFromArbiterIDAndMsel(arbiter, i)}))
return getAmselFromArbiterIDAndMsel(arbiter, i);
tileOp->emitOpError("tile op arbiter ")
<< std::to_string(arbiter) << "has used up all its msels";
return -1;
};

std::vector<std::pair<std::pair<PhysPort, int>, SmallVector<PhysPort, 4>>>
sortedPacketFlows(packetFlows.begin(), packetFlows.end());

Expand Down Expand Up @@ -426,55 +461,67 @@ void AIEPathfinderPass::runOnPacketFlow(DeviceOp device, OpBuilder &builder) {
// If there is an assignment of an arbiter to a master port before, we
// assign all the master ports here with the same arbiter but different
// msel
bool foundMatchedDest = false;
bool foundMatchedDest =
false; // This switchbox's output channels match completely or partially
// with an existing amsel entry.
int foundPartialMatchArbiter =
-1; // This switchbox's output channels match partially with an existing
// amsel entry on this arbiter ID (-1 means null).
for (const auto &map : masterAMSels) {
if (map.first.first != tileOp)
continue;
amselValue = map.first.second;

// check if same destinations
SmallVector<Port, 4> ports(masterAMSels[{tileOp, amselValue}]);
if (ports.size() != packetFlow.second.size())
continue;

bool matched = true;
// check for complete/partial overlapping amsel -> port mapping with any
// previous amsel assignments
bool matched =
false; // Found at least one port with overlapping amsel assignment
bool mismatched = false; // Found at least one port without any
// overlapping amsel assignment
for (auto dest : packetFlow.second) {
if (Port port = dest.second;
std::find(ports.begin(), ports.end(), port) == ports.end()) {
matched = false;
break;
}
Port port = dest.second;
if (std::find(ports.begin(), ports.end(), port) == ports.end())
mismatched = true;
else
matched = true;
}

if (matched) {
foundMatchedDest = true;
if (mismatched)
foundPartialMatchArbiter = getArbiterIDFromAmsel(amselValue);
else if (ports.size() != packetFlow.second.size())
foundPartialMatchArbiter = getArbiterIDFromAmsel(amselValue);
break;
}
}

if (!foundMatchedDest) {
bool foundAMSelValue = false;
for (int a = 0; a < numArbiters; a++) {
for (int i = 0; i < numMsels; i++) {
amselValue = a + i * numArbiters;
if (masterAMSels.count({tileOp, amselValue}) == 0) {
foundAMSelValue = true;
break;
}
}

if (foundAMSelValue)
break;
// This packet flow switchbox's output ports completely mismatches with
// any existing amsel. Creating a new amsel.
amselValue = getNewUniqueAmsel(masterAMSels, tileOp);
// Update masterAMSels with new amsel
for (auto dest : packetFlow.second) {
Port port = dest.second;
masterAMSels[{tileOp, amselValue}].push_back(port);
}

} else if (foundPartialMatchArbiter >= 0) {
// This packet flow switchbox's output ports partially overlaps with some
// existing amsel. Creating a new amsel with the same arbiter.
amselValue = getNewUniqueAmselPerArbiterID(masterAMSels, tileOp,
foundPartialMatchArbiter);
// Update masterAMSels with new amsel
for (auto dest : packetFlow.second) {
Port port = dest.second;
masterAMSels[{tileOp, amselValue}].push_back(port);
}
}

slaveAMSels[packetFlow.first] = amselValue;
amselValues[tileOp] = amselValue % numArbiters;
amselValues[tileOp] = getArbiterIDFromAmsel(amselValue);
}

// Compute the master set IDs
Expand All @@ -485,8 +532,8 @@ void AIEPathfinderPass::runOnPacketFlow(DeviceOp device, OpBuilder &builder) {
assert(tileOp);
int amselValue = physPort.second;
for (auto port : ports) {
PhysPort physPort = {tileOp, port};
mastersets[physPort].push_back(amselValue);
PhysPort pp = {tileOp, port};
mastersets[pp].push_back(amselValue);
}
}

Expand Down Expand Up @@ -616,7 +663,7 @@ void AIEPathfinderPass::runOnPacketFlow(DeviceOp device, OpBuilder &builder) {
Block &b = swbox.getConnections().front();
builder.setInsertionPoint(b.getTerminator());

std::vector<bool> amselOpNeededVector(32);
std::vector<bool> amselOpNeededVector(numMsels * numArbiters);
for (const auto &map : mastersets) {
if (tileOp != map.first.first)
continue;
Expand All @@ -627,13 +674,16 @@ void AIEPathfinderPass::runOnPacketFlow(DeviceOp device, OpBuilder &builder) {
}
// Create all the amsel Ops
DenseMap<int, AMSelOp> amselOps;
for (int i = 0; i < 32; i++) {
if (amselOpNeededVector[i]) {
int arbiterID = i % numArbiters;
int msel = i / numArbiters;
auto amsel =
builder.create<AMSelOp>(builder.getUnknownLoc(), arbiterID, msel);
amselOps[i] = amsel;
for (int i = 0; i < numMsels; i++) {
for (int a = 0; a < numArbiters; a++) {
auto amselValue = getAmselFromArbiterIDAndMsel(a, i);
if (amselOpNeededVector[amselValue]) {
int arbiterID = a;
int msel = i;
auto amsel =
builder.create<AMSelOp>(builder.getUnknownLoc(), arbiterID, msel);
amselOps[amselValue] = amsel;
}
}
}
// Create all the master set Ops
Expand Down
2 changes: 1 addition & 1 deletion test/create-packet-flows/test_create_packet_flows0.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,7 @@ module @test_create_packet_flows0 {
// CHECK: %[[VAL_1:.*]] = aie.switchbox(%[[VAL_0]]) {
// The actual indices used for the amsel arguments is unimportant.
// CHECK: %[[VAL_6:.*]] = aie.amsel<0> (0)
// CHECK: %[[VAL_7:.*]] = aie.amsel<0> (1)
// CHECK: %[[VAL_7:.*]] = aie.amsel<1> (0)
// CHECK: %[[VAL_4:.*]] = aie.masterset(Core : 0, %[[VAL_2:.*]])
// CHECK: %[[VAL_5:.*]] = aie.masterset(Core : 1, %[[VAL_3:.*]])
// CHECK: aie.packet_rules(West : 0) {
Expand Down
2 changes: 1 addition & 1 deletion test/create-packet-flows/test_create_packet_flows4.mlir
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Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,7 @@ module @test_create_packet_flows4 {
// CHECK: %[[VAL_0:.*]] = aie.tile(1, 1)
// CHECK: %[[VAL_1:.*]] = aie.switchbox(%[[VAL_0]]) {
// CHECK: %[[VAL_6:.*]] = aie.amsel<0> (0)
// CHECK: %[[VAL_7:.*]] = aie.amsel<0> (1)
// CHECK: %[[VAL_7:.*]] = aie.amsel<1> (0)
// CHECK: %[[VAL_4:.*]] = aie.masterset(Core : 0, %[[VAL_3:.*]])
// CHECK: %[[VAL_5:.*]] = aie.masterset(Core : 1, %[[VAL_2:.*]])
// CHECK: aie.packet_rules(West : 1) {
Expand Down

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