Add +RTS -vg flag for requesting some GC trace messages, outside DEBUG

DEBUG imposes a significant performance hit in the GC, yet we often
want some of the debugging output, so -vg gives us the cheap trace
messages without the sanity checking of DEBUG, just like -vs for the
scheduler.

1 files changed, 8 insertions, 0 deletions

diff --git a/rts/sm/GC.h b/rts/sm/GC.h
index f98e4a1535..5183837f1e 100644
--- a/rts/sm/GC.h
+++ b/rts/sm/GC.h
@@ -148,6 +148,14 @@ typedef struct gc_thread_ {
 #endif
 
     // -------------------
+    // stats
+
+    lnat copied;
+    lnat any_work;
+    lnat scav_global_work;
+    lnat scav_local_work;
+
+    // -------------------
     // workspaces
 
     // array of workspaces, indexed by stp->abs_no.  This is placed