Refactoring and tidy up

This is a port of some of the changes from my private local-GC branch
(which is still in darcs, I haven't converted it to git yet).  There
are a couple of small functional differences in the GC stats: first,
per-thread GC timings should now be more accurate, and secondly we now
report average and maximum pause times. e.g. from minimax +RTS -N8 -s:

                                    Tot time (elapsed)  Avg pause  Max pause
  Gen  0      2755 colls,  2754 par   13.16s    0.93s     0.0003s    0.0150s
  Gen  1       769 colls,   769 par    3.71s    0.26s     0.0003s    0.0059s

1 files changed, 9 insertions, 4 deletions

diff --git a/rts/Stats.h b/rts/Stats.h
index f3a20ae6a2..0c5178723c 100644
--- a/rts/Stats.h
+++ b/rts/Stats.h
@@ -13,13 +13,18 @@
 
 #include "BeginPrivate.h"
 
+struct gc_thread_;
+
 void      stat_startInit(void);
 void      stat_endInit(void);
 
-void      stat_startGC(void);
-void      stat_endGC (lnat alloc, lnat live, 
-		      lnat copied, lnat gen,
-                      lnat max_copied, lnat avg_copied, lnat slop);
+void      stat_startGC(struct gc_thread_ *gct);
+void      stat_endGC  (struct gc_thread_ *gct, lnat alloc, lnat live, 
+		       lnat copied, nat gen,
+                       lnat max_copied, lnat avg_copied, lnat slop);
+
+void stat_gcWorkerThreadStart (struct gc_thread_ *gct);
+void stat_gcWorkerThreadDone  (struct gc_thread_ *gct);
 
 #ifdef PROFILING
 void      stat_startRP(void);