Fix PME run mode without PME

pmeRunMode was incorrectly set to CPU when the PME task is not
assigned to a GPU in a non-PME run.
This change make sure that non-PME runs pmeRunMode is correctly set to
None. It also moves this setup code to a function in the taskassignment
module.

Change-Id: I2c2c609e56d3cb6eef5cfccf2f0489545cedf6ef

diff --git a/src/gromacs/mdrun/runner.cpp b/src/gromacs/mdrun/runner.cpp
index bae0c18e960081dcde47628192aaefd7b85e9b1c..b66f48729132a5d67da39053bfdfc5232d270852 100644 (file)
--- a/src/gromacs/mdrun/runner.cpp
+++ b/src/gromacs/mdrun/runner.cpp
@@ -729,12 +729,11 @@ int Mdrunner::mdrunner()
         userGpuTaskAssignment = parseUserTaskAssignmentString(hw_opt.userGpuTaskAssignment);
     }
     GMX_CATCH_ALL_AND_EXIT_WITH_FATAL_ERROR
-    auto       nonbondedTarget = findTaskTarget(nbpu_opt);
-    auto       pmeTarget       = findTaskTarget(pme_opt);
-    auto       pmeFftTarget    = findTaskTarget(pme_fft_opt);
-    auto       bondedTarget    = findTaskTarget(bonded_opt);
-    auto       updateTarget    = findTaskTarget(update_opt);
-    PmeRunMode pmeRunMode      = PmeRunMode::None;
+    auto nonbondedTarget = findTaskTarget(nbpu_opt);
+    auto pmeTarget       = findTaskTarget(pme_opt);
+    auto pmeFftTarget    = findTaskTarget(pme_fft_opt);
+    auto bondedTarget    = findTaskTarget(bonded_opt);
+    auto updateTarget    = findTaskTarget(update_opt);
 
     FILE* fplog = nullptr;
     // If we are appending, we don't write log output because we need
@@ -884,24 +883,11 @@ int Mdrunner::mdrunner()
                 useGpuForNonbonded, useGpuForPme, bondedTarget, canUseGpuForBonded,
                 EVDW_PME(inputrec->vdwtype), EEL_PME_EWALD(inputrec->coulombtype),
                 domdecOptions.numPmeRanks, gpusWereDetected);
-
-        pmeRunMode = (useGpuForPme ? PmeRunMode::GPU : PmeRunMode::CPU);
-        if (pmeRunMode == PmeRunMode::GPU)
-        {
-            if (pmeFftTarget == TaskTarget::Cpu)
-            {
-                pmeRunMode = PmeRunMode::Mixed;
-            }
-        }
-        else if (pmeFftTarget == TaskTarget::Gpu)
-        {
-            gmx_fatal(FARGS,
-                      "Assigning FFTs to GPU requires PME to be assigned to GPU as well. With PME "
-                      "on CPU you should not be using -pmefft.");
-        }
     }
     GMX_CATCH_ALL_AND_EXIT_WITH_FATAL_ERROR
 
+    const PmeRunMode pmeRunMode = determinePmeRunMode(useGpuForPme, pmeFftTarget, *inputrec);
+
     // Initialize development feature flags that enabled by environment variable
     // and report those features that are enabled.
     const DevelopmentFeatureFlags devFlags =

diff --git a/src/gromacs/taskassignment/decidegpuusage.cpp b/src/gromacs/taskassignment/decidegpuusage.cpp
index 3974e7b013fcf103cdbf74c4cad9a6decbc6e874..ea249317da77db3d5bd6c338bd71d9541d263e8c 100644 (file)
--- a/src/gromacs/taskassignment/decidegpuusage.cpp
+++ b/src/gromacs/taskassignment/decidegpuusage.cpp
@@ -1,7 +1,7 @@
 /*
  * This file is part of the GROMACS molecular simulation package.
  *
- * Copyright (c) 2015,2016,2017,2018,2019, by the GROMACS development team, led by
+ * Copyright (c) 2015,2016,2017,2018,2019,2020, by the GROMACS development team, led by
  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
  * and including many others, as listed in the AUTHORS file in the
  * top-level source directory and at http://www.gromacs.org.
@@ -428,6 +428,37 @@ bool decideWhetherToUseGpusForPme(const bool              useGpuForNonbonded,
     return false;
 }
 
+
+PmeRunMode determinePmeRunMode(const bool useGpuForPme, const TaskTarget& pmeFftTarget, const t_inputrec& inputrec)
+{
+    if (!EEL_PME(inputrec.coulombtype))
+    {
+        return PmeRunMode::None;
+    }
+
+    if (useGpuForPme)
+    {
+        if (pmeFftTarget == TaskTarget::Cpu)
+        {
+            return PmeRunMode::Mixed;
+        }
+        else
+        {
+            return PmeRunMode::GPU;
+        }
+    }
+    else
+    {
+        if (pmeFftTarget == TaskTarget::Gpu)
+        {
+            gmx_fatal(FARGS,
+                      "Assigning FFTs to GPU requires PME to be assigned to GPU as well. With PME "
+                      "on CPU you should not be using -pmefft.");
+        }
+        return PmeRunMode::CPU;
+    }
+}
+
 bool decideWhetherToUseGpusForBonded(const bool       useGpuForNonbonded,
                                      const bool       useGpuForPme,
                                      const TaskTarget bondedTarget,

diff --git a/src/gromacs/taskassignment/decidegpuusage.h b/src/gromacs/taskassignment/decidegpuusage.h
index 6d22cf843ae1efb509f97d4905945e3ecba6ed49..921b0a778bdf14e626ea63cf8424c92038999405 100644 (file)
--- a/src/gromacs/taskassignment/decidegpuusage.h
+++ b/src/gromacs/taskassignment/decidegpuusage.h
@@ -1,7 +1,7 @@
 /*
  * This file is part of the GROMACS molecular simulation package.
  *
- * Copyright (c) 2017,2018,2019, by the GROMACS development team, led by
+ * Copyright (c) 2017,2018,2019,2020, by the GROMACS development team, led by
  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
  * and including many others, as listed in the AUTHORS file in the
  * top-level source directory and at http://www.gromacs.org.
@@ -209,6 +209,20 @@ bool decideWhetherToUseGpusForPme(bool                    useGpuForNonbonded,
                                   int                     numPmeRanksPerSimulation,
                                   bool                    gpusWereDetected);
 
+/*! \brief Determine PME run mode.
+ *
+ * Given the PME task assignment in \p useGpuForPme and the user-provided
+ * FFT task target in \p pmeFftTarget, returns a PME run mode for the
+ * current run. It also checks the compatibility of the two.
+ *
+ * \note Aborts the run upon incompatible values of \p useGpuForPme and \p pmeFftTarget.
+ *
+ * \param[in]  useGpuForPme              PME task assignment, true if PME task is mapped to the GPU.
+ * \param[in]  pmeFftTarget              The user's choice for -pmefft for where to assign the FFT
+ * work of the PME task. \param[in]  inputrec                  The user input record
+ * */
+PmeRunMode determinePmeRunMode(bool useGpuForPme, const TaskTarget& pmeFftTarget, const t_inputrec& inputrec);
+
 /*! \brief Decide whether the simulation will try to run bonded tasks on GPUs.
  *
  * \param[in]  useGpuForNonbonded        Whether GPUs will be used for nonbonded interactions.