Implement public interface for GC statistics.

We add a new RTS flag -T for collecting statistics but not giving any
new inputs.  There is one new struct in rts/storage/GC.h: GCStats.  We
add two new global counters current_residency and current_slop, which
are useful for in-program GC statistics.

See GHC.Stats in base for a Haskell interface to this functionality.

Signed-off-by: Edward Z. Yang <ezyang@mit.edu>

1 files changed, 44 insertions, 0 deletions

diff --git a/includes/rts/storage/GC.h b/includes/rts/storage/GC.h
index 3c6e6f6e26..e57ffd23cf 100644
--- a/includes/rts/storage/GC.h
+++ b/includes/rts/storage/GC.h
@@ -181,6 +181,50 @@ void setKeepCAFs (void);
    Stats
    -------------------------------------------------------------------------- */
 
+typedef struct _GCStats {
+  StgWord64 bytes_allocated;
+  StgWord64 num_gcs;
+  StgWord64 num_byte_usage_samples;
+  StgWord64 max_bytes_used;
+  StgWord64 cumulative_bytes_used;
+  StgWord64 bytes_copied;
+  StgWord64 current_bytes_used;
+  StgWord64 current_bytes_slop;
+  StgWord64 max_bytes_slop;
+  StgWord64 peak_megabytes_allocated;
+  StgWord64 par_avg_bytes_copied;
+  StgWord64 par_max_bytes_copied;
+  StgDouble mutator_cpu_seconds;
+  StgDouble mutator_wall_seconds;
+  StgDouble gc_cpu_seconds;
+  StgDouble gc_wall_seconds;
+} GCStats;
+void getGCStats (GCStats *s);
+
+// These don't change over execution, so do them elsewhere
+//  StgDouble init_cpu_seconds;
+//  StgDouble init_wall_seconds;
+
+typedef struct _ParGCStats {
+  StgWord64 avg_copied;
+  StgWord64 max_copied;
+} ParGCStats;
+void getParGCStats (ParGCStats *s);
+
+/*
+typedef struct _TaskStats {
+  StgWord64 mut_time;
+  StgWord64 mut_etime;
+  StgWord64 gc_time;
+  StgWord64 gc_etime;
+} TaskStats;
+// would need to allocate arbitrarily large amount of memory
+// because it's a linked list of results
+void getTaskStats (TaskStats **s);
+// Need to stuff SparkCounters in a public header file...
+void getSparkStats (SparkCounters *s);
+*/
+
 // Returns the total number of bytes allocated since the start of the program.
 HsInt64 getAllocations (void);