Refactor string handling for GPU usage report

This prepares for future addition of reporting the list of available
compatible GPUs in the auto-selection case, which is needed for gmx
tune-pme to function well. Current outputs are only of IDs of
available GPUs, or IDs of those that will be used. The latter depends
on the number of PP ranks, so it doesn't help gmx tune-pme find out
how to run the optimization. At some point, delegating this kind of
task to hwinfo called from gmx tune-pme might be preferable.

The only functionality changes here are of reporting GPU ids by
referring to them as IDs, and the string of the ones used is of style
"0,1,4" rather than "#0, #1, #4". The use of the template function and
constructing the temporary vector prepares for the next commit.

Change-Id: Ic37989ce2f8e6396f450e1b5457ea7ea70b3849b

diff --git a/src/gromacs/gmxlib/gmx_detect_hardware.cpp b/src/gromacs/gmxlib/gmx_detect_hardware.cpp
index e5478b00202cea6d0f027e9d161350530bab7a92..385bdee82e471b1c36acf403256b7aff1354d9cb 100644 (file)
--- a/src/gromacs/gmxlib/gmx_detect_hardware.cpp
+++ b/src/gromacs/gmxlib/gmx_detect_hardware.cpp
@@ -36,6 +36,9 @@
 #include <config.h>
 #endif
 
+#include <string>
+#include <vector>
+
 #include <assert.h>
 #include <errno.h>
 #include <stdlib.h>
@@ -59,9 +62,11 @@
 
 #include "gromacs/utility/basenetwork.h"
 #include "gromacs/utility/cstringutil.h"
+#include "gromacs/utility/exceptions.h"
 #include "gromacs/utility/fatalerror.h"
 #include "gromacs/utility/gmxomp.h"
 #include "gromacs/utility/smalloc.h"
+#include "gromacs/utility/stringutil.h"
 
 #include "thread_mpi/threads.h"
 
@@ -147,50 +152,74 @@ static void print_gpu_detection_stats(FILE                 *fplog,
     }
 }
 
-static void print_gpu_use_stats(FILE                 *fplog,
-                                const gmx_gpu_info_t *gpu_info,
-                                const gmx_gpu_opt_t  *gpu_opt,
-                                const t_commrec      *cr)
+/*! \brief Helper function for writing comma-separated GPU IDs.
+ *
+ * \param[in] ids  A container of integer GPU IDs
+ * \return         A comma-separated string of GPU IDs */
+template <typename Container>
+static std::string makeGpuIdsString(const Container &ids)
 {
-    char sbuf[STRLEN], stmp[STRLEN];
-    int  i, ngpu_comp, ngpu_use;
+    std::string output;
 
-    ngpu_comp = gpu_info->ncuda_dev_compatible;
-    ngpu_use  = gpu_opt->ncuda_dev_use;
+    if (0 != ids.size())
+    {
+        typename Container::const_iterator it = ids.begin();
+        output += gmx::formatString("%d", *it);
+        for (++it; it != ids.end(); ++it)
+        {
+            output += gmx::formatString(",%d", *it);
+        }
+    }
+    return output;
+}
+
+/*! \brief Helper function for reporting GPU usage information
+ * in the mdrun log file
+ *
+ * \param[in] gpu_info    Pointer to per-node GPU info struct
+ * \param[in] gpu_opt     Pointer to per-node GPU options struct
+ * \param[in] numPpRanks  Number of PP ranks per node
+ * \return                String to write to the log file
+ * \throws                std::bad_alloc if out of memory */
+static std::string
+makeGpuUsageReport(const gmx_gpu_info_t *gpu_info,
+                   const gmx_gpu_opt_t  *gpu_opt,
+                   size_t                numPpRanks)
+{
+    int ngpu_use  = gpu_opt->ncuda_dev_use;
+    int ngpu_comp = gpu_info->ncuda_dev_compatible;
 
     /* Issue a note if GPUs are available but not used */
     if (ngpu_comp > 0 && ngpu_use < 1)
     {
-        sprintf(sbuf,
-                "%d compatible GPU%s detected in the system, but none will be used.\n"
-                "Consider trying GPU acceleration with the Verlet scheme!",
-                ngpu_comp, (ngpu_comp > 1) ? "s" : "");
+        return gmx::formatString("%d compatible GPU%s detected in the system, but none will be used.\n"
+                                 "Consider trying GPU acceleration with the Verlet scheme!\n",
+                                 ngpu_comp, (ngpu_comp > 1) ? "s" : "");
     }
-    else
-    {
-        int ngpu_use_uniq;
-
-        ngpu_use_uniq = gmx_count_gpu_dev_unique(gpu_info, gpu_opt);
 
-        sprintf(sbuf, "%d GPU%s %sselected for this run.\n"
-                "Mapping of GPU%s to the %d PP rank%s in this node: ",
-                ngpu_use_uniq, (ngpu_use_uniq > 1) ? "s" : "",
-                gpu_opt->bUserSet ? "user-" : "auto-",
-                (ngpu_use > 1) ? "s" : "",
-                cr->nrank_pp_intranode,
-                (cr->nrank_pp_intranode > 1) ? "s" : "");
+    std::string output;
 
-        for (i = 0; i < ngpu_use; i++)
+    {
+        std::vector<int> gpuIdsInUse;
+        for (int i = 0; i < ngpu_use; i++)
         {
-            sprintf(stmp, "#%d", get_gpu_device_id(gpu_info, gpu_opt, i));
-            if (i < ngpu_use - 1)
-            {
-                strcat(stmp, ", ");
-            }
-            strcat(sbuf, stmp);
+            gpuIdsInUse.push_back(get_gpu_device_id(gpu_info, gpu_opt, i));
         }
+        std::string gpuIdsString = makeGpuIdsString(gpuIdsInUse);
+        int         numGpusInUse = gmx_count_gpu_dev_unique(gpu_info, gpu_opt);
+        bool        bPluralGpus  = numGpusInUse > 1;
+
+        output += gmx::formatString("%d GPU%s %sselected for this run.\n"
+                                    "Mapping of GPU ID%s to the %d PP rank%s in this node: %s\n",
+                                    numGpusInUse, bPluralGpus ? "s" : "",
+                                    gpu_opt->bUserSet ? "user-" : "auto-",
+                                    bPluralGpus ? "s" : "",
+                                    numPpRanks,
+                                    (numPpRanks > 1) ? "s" : "",
+                                    gpuIdsString.c_str());
     }
-    md_print_info(cr, fplog, "%s\n\n", sbuf);
+
+    return output;
 }
 
 /* Give a suitable fatal error or warning if the build configuration
@@ -281,8 +310,17 @@ void gmx_check_hw_runconf_consistency(FILE                *fplog,
 
     if (hwinfo->gpu_info.ncuda_dev_compatible > 0)
     {
+        std::string gpuUseageReport;
+        try
+        {
+            gpuUseageReport = makeGpuUsageReport(&hwinfo->gpu_info,
+                                                 &hw_opt->gpu_opt,
+                                                 cr->nrank_pp_intranode);
+        }
+        GMX_CATCH_ALL_AND_EXIT_WITH_FATAL_ERROR;
+
         /* NOTE: this print is only for and on one physical node */
-        print_gpu_use_stats(fplog, &hwinfo->gpu_info, &hw_opt->gpu_opt, cr);
+        md_print_info(cr, fplog, gpuUseageReport.c_str());
     }
 
     /* Need to ensure that we have enough GPUs: