nonmoving: Fix documentation of GC statistics fields

These were previously incorrect.

Fixes #21553.

2 files changed, 17 insertions, 25 deletions

diff --git a/libraries/base/GHC/Stats.hsc b/libraries/base/GHC/Stats.hsc
index 7b5c0cd463..0d772ba765 100644
--- a/libraries/base/GHC/Stats.hsc
+++ b/libraries/base/GHC/Stats.hsc
@@ -105,23 +105,20 @@ data RTSStats = RTSStats {
     -- | Total elapsed time (at the previous GC)
   , elapsed_ns :: RtsTime
 
-    -- | The CPU time used during the post-mark pause phase of the concurrent
-    -- nonmoving GC.
+    -- | The total CPU time used during the post-mark pause phase of the
+    -- concurrent nonmoving GC.
   , nonmoving_gc_sync_cpu_ns :: RtsTime
-    -- | The time elapsed during the post-mark pause phase of the concurrent
-    -- nonmoving GC.
+    -- | The total time elapsed during the post-mark pause phase of the
+    -- concurrent nonmoving GC.
   , nonmoving_gc_sync_elapsed_ns :: RtsTime
-    -- | The maximum time elapsed during the post-mark pause phase of the
+    -- | The maximum elapsed length of any post-mark pause phase of the
     -- concurrent nonmoving GC.
   , nonmoving_gc_sync_max_elapsed_ns :: RtsTime
-    -- | The CPU time used during the post-mark pause phase of the concurrent
-    -- nonmoving GC.
+    -- | The total CPU time used by the nonmoving GC.
   , nonmoving_gc_cpu_ns :: RtsTime
-    -- | The time elapsed during the post-mark pause phase of the concurrent
-    -- nonmoving GC.
+    -- | The total time elapsed during which there is a nonmoving GC active.
   , nonmoving_gc_elapsed_ns :: RtsTime
-    -- | The maximum time elapsed during the post-mark pause phase of the
-    -- concurrent nonmoving GC.
+    -- | The maximum time elapsed during any nonmoving GC cycle.
   , nonmoving_gc_max_elapsed_ns :: RtsTime
 
     -- | Details about the most recent GC
diff --git a/rts/include/RtsAPI.h b/rts/include/RtsAPI.h
index e2d1845819..b6ea88623c 100644
--- a/rts/include/RtsAPI.h
+++ b/rts/include/RtsAPI.h
@@ -176,11 +176,9 @@ typedef struct GCDetails_ {
     // The time elapsed during the post-mark pause phase of the concurrent
     // nonmoving GC.
   Time nonmoving_gc_sync_elapsed_ns;
-    // The CPU time used during the post-mark pause phase of the concurrent
-    // nonmoving GC.
+    // The total CPU time used by the nonmoving GC.
   Time nonmoving_gc_cpu_ns;
-    // The time elapsed during the post-mark pause phase of the concurrent
-    // nonmoving GC.
+    // The total time elapsed during which there is a nonmoving GC active.
   Time nonmoving_gc_elapsed_ns;
 } GCDetails;
 
@@ -261,23 +259,20 @@ typedef struct _RTSStats {
   // ----------------------------------
   // Concurrent garbage collector
 
-    // The CPU time used during the post-mark pause phase of the concurrent
-    // nonmoving GC.
+    // The total CPU time used during the post-mark pause phase of the
+    // concurrent nonmoving GC.
   Time nonmoving_gc_sync_cpu_ns;
-    // The time elapsed during the post-mark pause phase of the concurrent
-    // nonmoving GC.
+    // The total time elapsed during the post-mark pause phase of the
+    // concurrent nonmoving GC.
   Time nonmoving_gc_sync_elapsed_ns;
     // The maximum time elapsed during the post-mark pause phase of the
     // concurrent nonmoving GC.
   Time nonmoving_gc_sync_max_elapsed_ns;
-    // The CPU time used during the post-mark pause phase of the concurrent
-    // nonmoving GC.
+    // The total CPU time used by the nonmoving GC.
   Time nonmoving_gc_cpu_ns;
-    // The time elapsed during the post-mark pause phase of the concurrent
-    // nonmoving GC.
+    // The total time elapsed during which there is a nonmoving GC active.
   Time nonmoving_gc_elapsed_ns;
-    // The maximum time elapsed during the post-mark pause phase of the
-    // concurrent nonmoving GC.
+    // The maximum time elapsed during any nonmoving GC cycle.
   Time nonmoving_gc_max_elapsed_ns;
 } RTSStats;