diff --git a/garlic/exp/fwi/common.nix b/garlic/exp/fwi/common.nix
index cbc49a4..e9a6d41 100644
--- a/garlic/exp/fwi/common.nix
+++ b/garlic/exp/fwi/common.nix
@@ -40,67 +40,70 @@ rec {
     ntasksPerNode = hw.cpusPerNode;
   };
 
-  srun = {nextStage, conf, ...}:
+  exec = {nextStage, conf, ...}:
   let
     fwiParams = bsc.apps.fwi.params.override {
       inherit (conf) nx ny nz;
     };
-  in
-    stdexp.stdStages.srun {
-      inherit nextStage conf;
-      # Now we add some commands to execute before calling srun. These will
-      # only run in one rank (the first in the list of allocated nodes)
-      preSrun = ''
-        export GARLIC_FWI_SRUNDIR=$(pwd)
-        export GARLIC_FWI_EXECDIR="${conf.tempDir}/out/$GARLIC_USER/$GARLIC_UNIT/$GARLIC_RUN"
-        mkdir -p "$GARLIC_FWI_EXECDIR"
-
-        export GARLIC_FWI_PARAMS="${fwiParams}/fwi_params.txt"
-        export GARLIC_FWI_FREQ="${fwiParams}/fwi_frequencies.txt"
-
-        # We cannot change the working directory of srun, so we use a
-        # subshell to ignore the cd
-        (
-          # Generate the input dataset
-          >&2 echo "generating the input dataset"
-          cd "$GARLIC_FWI_EXECDIR"
-          ${fwiParams}/bin/ModelGenerator \
-            -m "$GARLIC_FWI_PARAMS" "$GARLIC_FWI_FREQ"
-        )
-      '';
-
-      postSrun = optionalString (conf.enableCTF) ''
-        # Save the traces
-        mv "$GARLIC_FWI_EXECDIR"/trace_* .
-      '' + ''
-        # Remove everything else
-        rm -rf "$GARLIC_FWI_EXECDIR"
-      '';
-    };
-
-  exec = {nextStage, conf, ...}: stages.exec {
+  in stages.exec {
     inherit nextStage;
 
     # FIXME: FWI should allow the I/O directory to be specified as a
     # parameter
     pre = ''
-      # Run fwi at the in a directory with fast local storage
-      cd "$GARLIC_FWI_EXECDIR"
+      FWI_SRUNDIR=$(pwd)
+      FWI_EXECDIR="${conf.tempDir}/out/$GARLIC_USER/$GARLIC_UNIT/$GARLIC_RUN"
+      FWI_PARAMS="${fwiParams}/fwi_params.txt"
+      FWI_FREQ="${fwiParams}/fwi_frequencies.txt"
+
+      # Run fwi in a directory with fast local storage
+      mkdir -p "$FWI_EXECDIR"
+      cd "$FWI_EXECDIR"
+
+      # Only generate the input if we have the CPU 0 (once per node)
+      if grep -o 'Cpus_allowed_list:[[:space:]]0' \
+        /proc/self/status > /dev/null;
+      then
+        FWI_CAPTAIN=1
+      fi
+
+      if [ $FWI_CAPTAIN ]; then
+        >&2 echo "generating the input dataset"
+        ${fwiParams}/bin/ModelGenerator -m "$FWI_PARAMS" "$FWI_FREQ"
+      fi
 
       echo >&2 "Current dir: $(pwd)"
-      echo >&2 "Using PARAMS=$GARLIC_FWI_PARAMS and FREQ=$GARLIC_FWI_FREQ"
+      echo >&2 "Using PARAMS=$FWI_PARAMS and FREQ=$FWI_FREQ"
     '' + optionalString (conf.enableCTF) ''
       export NANOS6_CONFIG_OVERRIDE="version.instrument=ctf"
     '';
 
     argv = [
-      ''"$GARLIC_FWI_PARAMS"''
-      ''"$GARLIC_FWI_FREQ"''
+      ''"$FWI_PARAMS"''
+      ''"$FWI_FREQ"''
     ] ++ optional (needsBlocksize conf) conf.blocksize ++ [
       "-1" # Fordward steps
       "-1" # Backward steps
       conf.ioFreq # Write/read frequency
     ];
+
+    post = ''
+      # Go back to the garlic out directory
+      cd "$FWI_SRUNDIR"
+
+      if [ $FWI_CAPTAIN ]; then
+    '' + optionalString (conf.enableCTF) ''
+        # FIXME: We should specify the path in the nanos6 config, so we
+        # can avoid the race condition while they are generating the
+        # traces
+        sleep 3
+
+        # Save the traces
+        mv "$FWI_EXECDIR"/trace_* .
+    '' + ''
+        rm -rf "$FWI_EXECDIR"
+      fi
+    '';
   };
 
   apps = bsc.garlic.apps;
@@ -117,8 +120,5 @@ rec {
       inherit fwiParams;
     };
 
-  pipeline = stdexp.stdPipelineOverride {
-    # Replace the stdandard srun stage with our own
-    overrides = { inherit srun; };
-  } ++ [ exec program ];
+  pipeline = stdexp.stdPipeline ++ [ exec program ];
 }