Fix heap profiling times

Now that the heap census runs in the middle of garbage collections,
the "CPU time" it was calculating included any CPU time used so far
in the current GC. This could cause CPU time to appear to go down,
which means hp2ps complained about "samples out of sequence".

I'm not sure if this is the nicest way to solve this (maybe resurrecting
mut_user_time_during_GC would be better?) but it gets things working again.

5 files changed, 14 insertions, 5 deletions

diff --git a/rts/ProfHeap.c b/rts/ProfHeap.c
index e88d7042ed..9d95b4ccc0 100644
--- a/rts/ProfHeap.c
+++ b/rts/ProfHeap.c
@@ -1071,14 +1071,14 @@ heapCensusChain( Census *census, bdescr *bd )
 }
 
 void
-heapCensus( void )
+heapCensus( Ticks t )
 {
   nat g, n;
   Census *census;
   gen_workspace *ws;
 
   census = &censuses[era];
-  census->time  = mut_user_time();
+  census->time  = mut_user_time_until(t);
     
   // calculate retainer sets if necessary
 #ifdef PROFILING
diff --git a/rts/ProfHeap.h b/rts/ProfHeap.h
index c4a92e200b..cf09c59231 100644
--- a/rts/ProfHeap.h
+++ b/rts/ProfHeap.h
@@ -9,9 +9,11 @@
 #ifndef PROFHEAP_H
 #define PROFHEAP_H
 
+#include "GetTime.h" // for Ticks
+
 #include "BeginPrivate.h"
 
-void    heapCensus         (void);
+void    heapCensus         (Ticks t);
 nat     initHeapProfiling  (void);
 void    endHeapProfiling   (void);
 rtsBool strMatchesSelector (char* str, char* sel);
diff --git a/rts/Stats.c b/rts/Stats.c
index 7c02b5a7d9..3aeb531254 100644
--- a/rts/Stats.c
+++ b/rts/Stats.c
@@ -84,11 +84,17 @@ Ticks stat_getElapsedTime(void)
    ------------------------------------------------------------------------ */
 
 double
+mut_user_time_until( Ticks t )
+{
+    return TICK_TO_DBL(t - GC_tot_cpu - PROF_VAL(RP_tot_time + HC_tot_time));
+}
+
+double
 mut_user_time( void )
 {
     Ticks cpu;
     cpu = getProcessCPUTime();
-    return TICK_TO_DBL(cpu - GC_tot_cpu - PROF_VAL(RP_tot_time + HC_tot_time));
+    return mut_user_time_until(cpu);
 }
 
 #ifdef PROFILING
diff --git a/rts/Stats.h b/rts/Stats.h
index 0c5178723c..8761be5669 100644
--- a/rts/Stats.h
+++ b/rts/Stats.h
@@ -50,6 +50,7 @@ void      initStats0(void);
 void      initStats1(void);
 
 double    mut_user_time_during_GC(void);
+double    mut_user_time_until(Ticks t);
 double    mut_user_time(void);
 
 #ifdef PROFILING
diff --git a/rts/sm/GC.c b/rts/sm/GC.c
index 2b9ee9d234..2252cfcd63 100644
--- a/rts/sm/GC.c
+++ b/rts/sm/GC.c
@@ -669,7 +669,7 @@ GarbageCollect (rtsBool force_major_gc,
   if (do_heap_census) {
       debugTrace(DEBUG_sched, "performing heap census");
       RELEASE_SM_LOCK;
-      heapCensus();
+      heapCensus(gct->gc_start_cpu);
       ACQUIRE_SM_LOCK;
   }