[c10d] Add a timeout check interval variable for timeout dump (pytorc…

…h#117093)

The current timeout check frequency is relied on monitoring thread's timeout thread which can be too long (even if we set it to 2mins) so let's use a separate timeout variable which users can configure it. And we only only let default PG to check TCPStore so even more frequent check should be fine. (Our stress test is performed on every half second).

Pull Request resolved: pytorch#117093
Approved by: https://github.com/wconstab, https://github.com/kwen2501

torch/csrc/distributed/c10d/ProcessGroupNCCL.cpp

@@ -770,6 +770,7 @@ ProcessGroupNCCL::ProcessGroupNCCL(
       getCvarInt(TORCH_NCCL_HEARTBEAT_TIMEOUT_SEC, 60 * 10 /*10 Mins*/);
   waitTimeoutDumpInMilSec_ =
       getCvarInt(TORCH_NCCL_WAIT_TIMEOUT_DUMP_MILSEC, 2000);
+  coordCheckIntervalMilSec_ = getCvarInt(TORCH_NCCL_COORD_CHECK_MILSEC, 1000);
   ncclTraceBufferSize_ = getCvarInt(TORCH_NCCL_TRACE_BUFFER_SIZE, 0);
   enableCollecticeHashDebug_ = (dist_debug_level_ >= DebugLevel::Detail);
   // store_ usually is wrapped with PrefixStore and the prefix is different
@@ -859,6 +860,7 @@ ProcessGroupNCCL::ProcessGroupNCCL(
             << monitorThreadEnabled_.load()
             << ", TORCH_NCCL_HEARTBEAT_TIMEOUT_SEC: " << heartbeatTimeoutInSec_
             << ", TORCH_NCCL_TRACE_BUFFER_SIZE: " << ncclTraceBufferSize_
+            << ", TORCH_NCCL_COORD_CHECK_MILSEC: " << coordCheckIntervalMilSec_
             << ", ID=" << this->getID();
 
   if (options_->global_ranks_in_group.empty()) {
@@ -1549,7 +1551,7 @@ void ProcessGroupNCCL::watchdogHandler() {
               (currentTime - lastTimePollStore))
               .count();
       if (timeSinceLastWorkListUpdate >= kWatchdogThreadSleepMillis &&
-          timeSinceLastPollStore >= heartbeatTimeoutInSec_ * 1000) {
+          timeSinceLastPollStore >= coordCheckIntervalMilSec_) {
         lastTimePollStore = currentTime;
         if (globalStore_->check({std::string(TIMEOUT_DUMP)}) &&
             !optAsyncDebugDump) {

torch/csrc/distributed/c10d/ProcessGroupNCCL.hpp

@@ -89,6 +89,11 @@ static std::vector<std::string> TORCH_NCCL_TRACE_BUFFER_SIZE = {
 static std::vector<std::string> TORCH_NCCL_WAIT_TIMEOUT_DUMP_MILSEC = {
     "TORCH_NCCL_WAIT_TIMEOUT_DUMP_MILSEC"};
 
+// Control the interval inside the watchdog thread to check the coordinated
+// signal from other ranks, e.g. to dump the debugging information.
+static std::vector<std::string> TORCH_NCCL_COORD_CHECK_MILSEC = {
+    "TORCH_NCCL_COORD_CHECK_MILSEC"};
+
 constexpr const char* NCCL_BACKEND_NAME = "nccl";
 
 constexpr const char* TIMEOUT_DUMP = "timeout_dump";
@@ -853,6 +858,10 @@ class TORCH_API ProcessGroupNCCL : public Backend {
   // Extra time of sleep when waiting for timeout dump to finish.
   int waitTimeoutDumpInMilSec_;
 
+  // Interval of check coordinated signals in ProcessGroupNCCL from other ranks
+  // e.g., trigger the dump of the debugging info for timeout when notified.
+  int coordCheckIntervalMilSec_;
+
   // Size of ring buffer where we store NCCL Traces for debugging.
   int ncclTraceBufferSize_;