half the number of calls to gc

src/Dataloaders.jl

@@ -193,7 +193,7 @@ function countlabels(repository, window; unload=false)
                 counts′[label] = get(counts′, label, 0) + 1
             end
         end
-        unload && unload!(file)
+        unload && unload!(file; gc=true)
         lock(c)
         try
             counts[file] = counts′
@@ -501,8 +501,8 @@ function sample(f, loader::DataLoader, features=:spine; kwargs...)
     Threads.foreach(ch) do (i, file, state)
         segments = sample(file, loader.window, loader.index, features; kwargs...)
         f(i, file, state, filter(!isnothing, segments))
-        empty!(segments) # `unload!` calls `GC.gc`
-        unload!(file)
+        empty!(segments)
+        unload!(file; gc=true)
     end
 end
 

src/Formats.jl

@@ -539,20 +539,20 @@ end
 
 Unload timeseries data to free memory space.
 """
-function unload!(file::Formats.JSONLabels)
+function unload!(file::Formats.JSONLabels; gc=false)
     for dep in file.dependencies
         unload!(dep)
     end
     empty!(file.dependencies)
     empty!(file.timeseries)
     empty!(file.run)
-    GC.gc()
+    gc && GC.gc()
     return file
 end
-function unload!(file)
+function unload!(file; gc=false)
     empty!(file.timeseries)
     empty!(file.run)
-    GC.gc()
+    gc && GC.gc()
     return file
 end