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Fix(io): track RDMA notification completions in transfer status #434

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11752f6
Fix(io): track RDMA notification completions in transfer status
dlimpus Jun 26, 2026
df59641
Fix(io): preserve notify count in WR-counted batches
dlimpus Jun 26, 2026
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43 changes: 33 additions & 10 deletions src/io/rdma/backend_impl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -738,13 +738,33 @@ NotifManager::FlushDrainStats NotifManager::ProcessOneCqe(
struct ibv_recv_wr* bad = nullptr;
SYSCALL_RETURN_ZERO(ibv_post_recv(ep.local.ibvHandle.qp, &wr, &bad));
} else if (wc[i].opcode == IBV_WC_SEND) {
if (!IsNotifSendWrId(wc[i].wr_id)) {
MORI_IO_WARN(
"ProcessOneCqe: unexpected SEND completion with non-notification wr_id {}; "
"releasing 1 sqDepth under current SEND invariant",
wc[i].wr_id);
if (IsNotifSendWrId(wc[i].wr_id)) {
// Backward-compatible handling for any notification SENDs posted by
// older code that used tagged transfer IDs instead of ledger records.
if (ep.sqDepth) ep.sqDepth->fetch_sub(1, std::memory_order_relaxed);
} else {
int mergedBatchSize = 0;
auto meta = ep.ledger
? ep.ledger->ReleaseByCqe(wc[i].wr_id, ep.sqDepth.get(), &mergedBatchSize)
: nullptr;
if (meta) {
uint32_t finishedBefore = meta->finishedBatchSize.fetch_add(mergedBatchSize);
TransferStatus* statusPtr = meta->status;
if (statusPtr != nullptr &&
(finishedBefore + mergedBatchSize) == meta->totalBatchSize) {
statusPtr->Update(StatusCode::SUCCESS, ibv_wc_status_str(wc[i].status));
}
MORI_IO_TRACE(
"ProcessOneCqe: notification SEND CQE for task {} total={} finished={} cur={}",
meta->id, meta->totalBatchSize, finishedBefore, mergedBatchSize);
} else {
MORI_IO_WARN(
"ProcessOneCqe: notification SEND CQE has no ledger record for wr_id {}; "
"releasing 1 sqDepth under fallback path",
wc[i].wr_id);
if (ep.sqDepth) ep.sqDepth->fetch_sub(1, std::memory_order_relaxed);
}
}
if (ep.sqDepth) ep.sqDepth->fetch_sub(1, std::memory_order_relaxed);
} else {
// Batch path: wr_id carries a recordId from the SubmissionLedger.
uint64_t recordId = wc[i].wr_id;
Expand Down Expand Up @@ -1198,7 +1218,8 @@ void RdmaBackendSession::ReadWrite(size_t localOffset, size_t remoteOffset, size
TransferStatus* status, TransferUniqueId id, bool isRead) {
MORI_IO_FUNCTION_TIMER;
status->SetCode(StatusCode::IN_PROGRESS);
auto callbackMeta = std::make_shared<CqCallbackMeta>(status, id, 1);
const int notifBatchSize = config.enableNotification ? static_cast<int>(eps.size()) : 0;
auto callbackMeta = std::make_shared<CqCallbackMeta>(status, id, 1 + notifBatchSize);
internal::PublishCurrentIoCallDiagnostics(callbackMeta);

RdmaOpRet ret = RdmaBatchReadWrite(eps, localMrPerEp, remoteMrPerEp, {localOffset},
Expand All @@ -1211,7 +1232,7 @@ void RdmaBackendSession::ReadWrite(size_t localOffset, size_t remoteOffset, size
status->Update(ret.code, ret.message);
}
if (!ret.Failed() && config.enableNotification) {
RdmaOpRet notifRet = RdmaNotifyTransfer(eps, status, id);
RdmaOpRet notifRet = RdmaNotifyTransfer(eps, callbackMeta, id);
if (notifRet.Failed()) {
status->Update(notifRet.code, notifRet.message);
}
Expand All @@ -1223,7 +1244,9 @@ void RdmaBackendSession::BatchReadWrite(const SizeVec& localOffsets, const SizeV
TransferUniqueId id, bool isRead) {
MORI_IO_FUNCTION_TIMER;
status->SetCode(StatusCode::IN_PROGRESS);
auto callbackMeta = std::make_shared<CqCallbackMeta>(status, id, sizes.size());
const int notifBatchSize = config.enableNotification ? static_cast<int>(eps.size()) : 0;
auto callbackMeta =
std::make_shared<CqCallbackMeta>(status, id, static_cast<int>(sizes.size()) + notifBatchSize);
internal::PublishCurrentIoCallDiagnostics(callbackMeta);
RdmaOpRet ret;
if (executor) {
Expand All @@ -1241,7 +1264,7 @@ void RdmaBackendSession::BatchReadWrite(const SizeVec& localOffsets, const SizeV
status->Update(ret.code, ret.message);
}
if (!ret.Failed() && config.enableNotification) {
RdmaOpRet notifRet = RdmaNotifyTransfer(eps, status, id);
RdmaOpRet notifRet = RdmaNotifyTransfer(eps, callbackMeta, id);
if (notifRet.Failed()) {
status->Update(notifRet.code, notifRet.message);
}
Expand Down
25 changes: 19 additions & 6 deletions src/io/rdma/common.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -370,9 +370,9 @@ static void ResetMergedWorkRequestPointers(MergedWorkRequest* wr) {
/* Rdma Utilities */
/* ---------------------------------------------------------------------------------------------- */

RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, TransferStatus* status, TransferUniqueId id) {
RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, std::shared_ptr<CqCallbackMeta> callbackMeta,
TransferUniqueId id) {
MORI_IO_FUNCTION_TIMER;
(void)status;

std::string reserveErr;
int reserved = 0;
Expand All @@ -388,6 +388,12 @@ RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, TransferStatus* status, Trans
}

for (size_t i = 0; i < eps.size(); i++) {
if (!eps[i].ledger) {
for (int j = static_cast<int>(i); j < reserved; ++j) ReleaseSqDepth(eps[j], 1);
return {StatusCode::ERR_RDMA_OP,
"submission ledger is not initialized for notification SEND tracking"};
}

const application::RdmaEndpoint& ep = eps[i].local;
NotifMessage msg{id, static_cast<int>(i), static_cast<int>(eps.size())};

Expand All @@ -396,8 +402,10 @@ RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, TransferStatus* status, Trans
sge.length = sizeof(NotifMessage);
sge.lkey = 0;

const uint64_t recordId = eps[i].ledger->Insert(1, true, callbackMeta, 1);

struct ibv_send_wr wr{};
wr.wr_id = MakeNotifSendWrId(id);
wr.wr_id = recordId;
wr.opcode = IBV_WR_SEND;
wr.send_flags = IBV_SEND_INLINE | IBV_SEND_SIGNALED;
wr.sg_list = &sge;
Expand All @@ -406,8 +414,11 @@ RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, TransferStatus* status, Trans
struct ibv_send_wr* bad_wr = nullptr;
int ret = ibv_post_send(ep.ibvHandle.qp, &wr, &bad_wr);
if (ret != 0) {
// WR i was reserved but failed to post if bad_wr points at this WR.
if (bad_wr == &wr) ReleaseSqDepth(eps[i], 1);
// This call posts a single WR, so a non-zero return means the current
// notification was not accepted and no CQE will arrive for its ledger record.
ReleaseSqDepth(eps[i], 1);
int dummy = 0;
eps[i].ledger->ReleaseByCqe(recordId, nullptr, &dummy);
// Any remaining endpoints are reserved but not posted yet.
for (int j = i + 1; j < eps.size(); ++j) ReleaseSqDepth(eps[j], 1);
std::string message =
Expand Down Expand Up @@ -675,8 +686,10 @@ RdmaOpRet RdmaBatchReadWrite(const EpPairVec& eps,
if (mergedWrCount > static_cast<size_t>(std::numeric_limits<int>::max())) {
return {StatusCode::ERR_INVALID_ARGS, "final WR count exceeds int range"};
}
const int notifBatchSize =
std::max(0, callbackMeta->totalBatchSize - static_cast<int>(batchSize));
for (size_t k = 0; k < mergedWrCount; ++k) mergedWrs[k].mergedRequests = 1;
callbackMeta->totalBatchSize = static_cast<int>(mergedWrCount);
callbackMeta->totalBatchSize = static_cast<int>(mergedWrCount) + notifBatchSize;
}

size_t epNum = eps.size();
Expand Down
3 changes: 2 additions & 1 deletion src/io/rdma/common.hpp
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Original file line number Diff line number Diff line change
Expand Up @@ -242,7 +242,8 @@ struct RdmaOpRet {
bool Failed() { return code > StatusCode::ERR_BEGIN; }
};

RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, TransferStatus* status, TransferUniqueId id);
RdmaOpRet RdmaNotifyTransfer(const EpPairVec& eps, std::shared_ptr<CqCallbackMeta> callbackMeta,
TransferUniqueId id);

RdmaOpRet RdmaBatchReadWrite(const EpPairVec& eps,
const std::vector<application::RdmaMemoryRegion>& localMrPerEp,
Expand Down
41 changes: 41 additions & 0 deletions tests/cpp/io/test_engine.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -246,6 +246,46 @@ void CaseSubmissionLedgerBasic() {
Require(sqDepth2.load(std::memory_order_relaxed) == 5, "sq depth after posted CQE release");
}

void CaseNotificationCompletionFanIn() {
TransferStatus status;
status.SetCode(StatusCode::IN_PROGRESS);
auto meta = std::make_shared<CqCallbackMeta>(&status, 42, 3);

uint32_t finishedBefore = meta->finishedBatchSize.fetch_add(2);
if (finishedBefore + 2 == meta->totalBatchSize) {
status.Update(StatusCode::SUCCESS, "data complete");
}
Require(status.InProgress(), "data completion must not finish before notification SEND CQE");

finishedBefore = meta->finishedBatchSize.fetch_add(1);
if (finishedBefore + 1 == meta->totalBatchSize) {
status.Update(StatusCode::SUCCESS, "notification complete");
}
Require(status.Succeeded(), "final notification completion should finish transfer");

TransferStatus outOfOrderStatus;
outOfOrderStatus.SetCode(StatusCode::IN_PROGRESS);
auto outOfOrderMeta = std::make_shared<CqCallbackMeta>(&outOfOrderStatus, 44, 5);
(void)outOfOrderMeta->finishedBatchSize.fetch_add(2); // notification SEND CQEs first
finishedBefore = outOfOrderMeta->finishedBatchSize.fetch_add(3);
if (finishedBefore + 3 == outOfOrderMeta->totalBatchSize) {
outOfOrderStatus.Update(StatusCode::SUCCESS, "data complete after notification");
}
Require(outOfOrderStatus.Succeeded(),
"notification-first completion order must still finish at the exact total");

TransferStatus failedStatus;
failedStatus.SetCode(StatusCode::IN_PROGRESS);
auto failedMeta = std::make_shared<CqCallbackMeta>(&failedStatus, 43, 2);
(void)failedMeta->finishedBatchSize.fetch_add(1);
failedStatus.Update(StatusCode::ERR_RDMA_OP, "notification failed");
finishedBefore = failedMeta->finishedBatchSize.fetch_add(1);
if (finishedBefore + 1 == failedMeta->totalBatchSize) {
failedStatus.Update(StatusCode::SUCCESS, "late success");
}
Require(failedStatus.Failed(), "notification failure must not be overwritten by late success");
}

void CaseWrIdNamespaceHelpers() {
const uint64_t taggedZero = MakeNotifSendWrId(0);
Require(taggedZero == kNotifSendWrIdTag, "tagged zero should only set the reserved high bit");
Expand Down Expand Up @@ -1451,6 +1491,7 @@ int main(int argc, char* argv[]) {
SetLogLevel("info");
std::vector<TestCase> cases = {
{"submission_ledger_basic", CaseSubmissionLedgerBasic},
{"notification_completion_fan_in", CaseNotificationCompletionFanIn},
{"wr_id_namespace_helpers", CaseWrIdNamespaceHelpers},
{"rdma_backend_config_chunking_fields", CaseRdmaBackendConfigChunkingFields},
{"resolve_requested_nics", CaseResolveRequestedNics},
Expand Down
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