[OpenMP][libomptarget] Considering OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT in NextGen plugins

[kevinsala]

Summary

Until now both OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT were accidentally ignored in the NextGen plugins. The maximum values reported by the devices were always used to compute the maximum number of teams and threads per team. This patch fixes this error and considers the values defined by those envars.

[kevinsala]

ping

[jdoerfert]

I thought the standard introduced device versions of these. Do we still honor these ones for the device? Can someone double check, please.

[kevinsala]

Already fixed in D145105.

[jhuber6]

Sorry, didn't notice this revision.

openmp/libomptarget/plugins-nextgen/common/PluginInterface/PluginInterface.cpp

: MemoryManager(nullptr), OMP_TeamLimit("OMP_TEAM_LIMIT"),
       // Do not initialize the following two envars since they depend on the
       // device initialization. These cannot be consulted until the device is
       // initialized correctly. We intialize them in GenericDeviceTy::init().
       OMPX_TargetStackSize(), OMPX_TargetHeapSize(),
       // By default, the initial number of streams and events are 32.
       OMPX_InitialNumStreams("LIBOMPTARGET_NUM_INITIAL_STREAMS", 32),
       OMPX_InitialNumEvents("LIBOMPTARGET_NUM_INITIAL_EVENTS", 32),
       DeviceId(DeviceId), GridValues(OMPGridValues),
-      PeerAccesses(NumDevices, PeerAccessState::PENDING), PeerAccessesLock() {
+      PeerAccesses(NumDevices, PeerAccessState::PENDING), PeerAccessesLock() {}
+
+Error GenericDeviceTy::init(GenericPluginTy &Plugin) {
+  if (auto Err = initImpl(Plugin))
+    return Err;
+
+  // Limit the maximum number of teams and team threads determined by the envars
+  // OMP_NUM_TEAMS and OMP_TEAMS_THREAD_LIMIT (if needed).
   if (OMP_NumTeams > 0)
     GridValues.GV_Max_Teams =
         std::min(GridValues.GV_Max_Teams, uint32_t(OMP_NumTeams));
 
   if (OMP_TeamsThreadLimit > 0)
     GridValues.GV_Max_WG_Size =
         std::min(GridValues.GV_Max_WG_Size, uint32_t(OMP_TeamsThreadLimit));
-}
-
-Error GenericDeviceTy::init(GenericPluginTy &Plugin) {
-  if (auto Err = initImpl(Plugin))
-    return Err;
 
   // Read and reinitialize the envars that depend on the device initialization.
   // Notice these two envars may change the stack size and heap size of the
   // device, so they need the device properly initialized.
   auto StackSizeEnvarOrErr = UInt64Envar::create(
       "LIBOMPTARGET_STACK_SIZE",
       [this](uint64_t &V) -> Error { return getDeviceStackSize(V); },
       [this](uint64_t V) -> Error { return setDeviceStackSize(V); });