Fix Work Balance computation in RTS stats

An additional stat is tracked per gc: par_balanced_copied This is the
the number of bytes copied by each gc thread under the balanced lmit,
which is simply (copied_bytes / num_gc_threads).  The stat is added to
all the appropriate GC structures, so is visible in the eventlog and in
GHC.Stats.

A note is added explaining how work balance is computed.

Remove some end of line whitespace

Test Plan:
./validate
experiment with the program attached to the ticket
examine code changes carefully

Reviewers: simonmar, austin, hvr, bgamari, erikd

Reviewed By: simonmar

Subscribers: Phyx, rwbarton, thomie

GHC Trac Issues: #13830

Differential Revision: https://phabricator.haskell.org/D3658

1 files changed, 1 insertions, 1 deletions

diff --git a/rts/Stats.h b/rts/Stats.h
index ff018716c4..5d9cf04fa7 100644
--- a/rts/Stats.h
+++ b/rts/Stats.h
@@ -30,7 +30,7 @@ void      stat_startGCSync(struct gc_thread_ *_gct);
 void      stat_startGC(Capability *cap, struct gc_thread_ *_gct);
 void      stat_endGC  (Capability *cap, struct gc_thread_ *_gct, W_ live,
                        W_ copied, W_ slop, uint32_t gen, uint32_t n_gc_threads,
-                       W_ par_max_copied);
+                       W_ par_max_copied, W_ par_balanced_copied);
 
 #if defined(PROFILING)
 void      stat_startRP(void);