[Haskell-cafe] System.Mem.performGC leaks?

main = forever performGC The OS reported memory usage skyrockets. If i enable +RTS -S the GC statistics show the heap "live bytes" being constant. Is it accumulating statistics even when profiling is disabled (and can you turn that off), or is there something going on with the FFI call to performGC. Compiled with "ghc -O2 -fvia-C -optc-O2 -funbox-strict-fields -threaded" btw.