Remove the location from the Score-P metric name

Author: Maximilian Sander

README.md

@@ -92,6 +92,12 @@ cmake -DMETRICQ_METRIC_PER_HOST=ON ...
 ```
 
 When using `per_host` mode, it is critical to ensure that only the rank(s) associated with a given node request metrics from MetricQ.
+This is controlled via the variable `SCOREP_METRIC_METRICQ_PLUGIN_PER_HOST_LOCATION`, which specifies the location of the metric.
+
+The value of `SCOREP_METRIC_METRICQ_PLUGIN_PER_HOST_LOCATION` must equal the prefix of the metrics listed in `SCOREP_METRIC_METRICQ_PLUGIN`.
+This design allows the metric location to be specified explicitly without requiring any modification of the metric string passed to `SCOREP_METRIC_METRICQ_PLUGIN`.
+In effect, location and metric name are separated while remaining consistent.
+
 On ZIH systems, this can be achieved by constructing node-specific metric names using SLURM environment variables.
 For example:
 
@@ -101,6 +107,7 @@ METRIC=power
 
 srun bash -c '
     export SCOREP_METRIC_METRICQ_PLUGIN=$SLURM_CLUSTER_NAME.$SLURMD_NODENAME.'"$METRIC"'
+    export SCOREP_METRIC_METRICQ_PLUGIN_PER_HOST_LOCATION=$SLURM_CLUSTER_NAME.$SLURMD_NODENAME
     exec '"$EXE"'
 '
 ```

src/main.cpp

@@ -20,6 +20,7 @@
 #include <vector>
 
 #include <cstdint>
+#include <cstdlib>
 
 using namespace scorep::plugin::policy;
 
@@ -57,6 +58,18 @@ void replace_all(std::string& str, const std::string& from, const std::string& t
     }
 }
 
+std::string remove_prefix(std::string name, const std::string& prefix)
+{
+    if (name.rfind(prefix, 0) == 0) {              // prefix at position 0
+        name.erase(0, prefix.size());
+        if (!name.empty() && name[0] == '.') {
+            name.erase(0, 1);                      // remove separator
+        }
+    }
+    return name;
+}
+
+
 template <typename T, typename Policies>
 using handle_oid_policy = object_id<Metric, T, Policies>;
 
@@ -104,6 +117,7 @@ class metricq_plugin : public scorep::plugin::base<metricq_plugin,
 public:
     std::vector<scorep::plugin::metric_property> get_metric_properties(const std::string& s)
     {
+        //
         auto metadata = get_metadata(s);
         std::vector<scorep::plugin::metric_property> result;
         for (const auto& elem : metadata)
@@ -118,11 +132,21 @@ class metricq_plugin : public scorep::plugin::base<metricq_plugin,
             }
 #endif
             auto use_average = use_timesync && average_;
+#ifdef METRICQ_METRIC_PER_HOST
+            std::string metric_prefix = "metricq_";
+            std::string per_host_location_env = scorep::environment_variable::get("PER_HOST_LOCATION", "");
+
+            std::string metric_name = metric_prefix + remove_prefix(name, std::string( per_host_location_env ));
+
+            make_handle(metric_name, Metric{ name, use_timesync, use_average });
+            auto property = scorep::plugin::metric_property(metric_name, meta.description(), meta.unit())
+                                .value_double();
+#else
             make_handle(name, Metric{ name, use_timesync, use_average });
 
             auto property = scorep::plugin::metric_property(name, meta.description(), meta.unit())
                                 .value_double();
-
+#endif
             if (use_average)
             {
                 property.absolute_last();