rts: remove no_work counter

We are no longer busyish waiting, so this is no longer meaningful

6 files changed, 6 insertions, 31 deletions

diff --git a/includes/RtsAPI.h b/includes/RtsAPI.h
index f88cd0614c..a5e4dfd623 100644
--- a/includes/RtsAPI.h
+++ b/includes/RtsAPI.h
@@ -266,9 +266,6 @@ typedef struct _RTSStats {
     // The number of times a GC thread has checked for work across all parallel
     // GCs
   uint64_t any_work;
-    // The number of times a GC thread has checked for work and found none
-    // across all parallel GCs
-  uint64_t no_work;
     // The number of times a GC thread has iterated it's outer loop across all
     // parallel GCs
   uint64_t scav_find_work;
diff --git a/rts/Stats.c b/rts/Stats.c
index cee1a2ad90..02616094b8 100644
--- a/rts/Stats.c
+++ b/rts/Stats.c
@@ -159,7 +159,6 @@ initStats0(void)
         .mut_spin_spin = 0,
         .mut_spin_yield = 0,
         .any_work = 0,
-        .no_work = 0,
         .scav_find_work = 0,
         .init_cpu_ns = 0,
         .init_elapsed_ns = 0,
@@ -461,8 +460,7 @@ void
 stat_endGC (Capability *cap, gc_thread *initiating_gct, W_ live, W_ copied, W_ slop,
             uint32_t gen, uint32_t par_n_threads, gc_thread **gc_threads,
             W_ par_max_copied, W_ par_balanced_copied, W_ gc_spin_spin, W_ gc_spin_yield,
-            W_ mut_spin_spin, W_ mut_spin_yield, W_ any_work, W_ no_work,
-            W_ scav_find_work)
+            W_ mut_spin_spin, W_ mut_spin_yield, W_ any_work, W_ scav_find_work)
 {
     ACQUIRE_LOCK(&stats_mutex);
 
@@ -542,7 +540,6 @@ stat_endGC (Capability *cap, gc_thread *initiating_gct, W_ live, W_ copied, W_ s
         stats.cumulative_par_balanced_copied_bytes +=
             stats.gc.par_balanced_copied_bytes;
         stats.any_work += any_work;
-        stats.no_work += no_work;
         stats.scav_find_work += scav_find_work;
         stats.gc_spin_spin += gc_spin_spin;
         stats.gc_spin_yield += gc_spin_yield;
@@ -1027,10 +1024,6 @@ static void report_summary(const RTSSummaryStats* sum)
                     , col_width[2], stats.any_work);
         statsPrintf("%*s" "%*s" "%*" FMT_Word64 "\n"
                     , col_width[0], ""
-                    , col_width[1], "no_work"
-                    , col_width[2], stats.no_work);
-        statsPrintf("%*s" "%*s" "%*" FMT_Word64 "\n"
-                    , col_width[0], ""
                     , col_width[1], "scav_find_work"
                     , col_width[2], stats.scav_find_work);
 #elif defined(THREADED_RTS) // THREADED_RTS && PROF_SPIN
@@ -1172,8 +1165,6 @@ static void report_machine_readable (const RTSSummaryStats * sum)
             whitehole_threadPaused_spin);
     MR_STAT("any_work", FMT_Word64,
             stats.any_work);
-    MR_STAT("no_work", FMT_Word64,
-            stats.no_work);
     MR_STAT("scav_find_work", FMT_Word64,
             stats.scav_find_work);
 #endif // PROF_SPIN
@@ -1619,10 +1610,7 @@ collector.
 
 Parallel garbage collector counters:
 * any_work:
-    A cheap function called whenever a gc_thread is ready for work. Does
-    not do any work.
-* no_work:
-    Incremented whenever any_work finds no work.
+    Incremented whenever a parallel GC looks for work to steal.
 * scav_find_work:
     Called to do work when any_work return true.
 
diff --git a/rts/Stats.h b/rts/Stats.h
index 9d62acef37..64aec2d5ee 100644
--- a/rts/Stats.h
+++ b/rts/Stats.h
@@ -37,8 +37,7 @@ void      stat_endGC  (Capability *cap, struct gc_thread_ *initiating_gct, W_ li
                        uint32_t n_gc_threads, struct gc_thread_ **gc_threads,
                        W_ par_max_copied, W_ par_balanced_copied,
                        W_ gc_spin_spin, W_ gc_spin_yield, W_ mut_spin_spin,
-                       W_ mut_spin_yield, W_ any_work, W_ no_work,
-                       W_ scav_find_work);
+                       W_ mut_spin_yield, W_ any_work, W_ scav_find_work);
 
 void      stat_startNonmovingGcSync(void);
 void      stat_endNonmovingGcSync(void);
diff --git a/rts/sm/GC.c b/rts/sm/GC.c
index 64a4c071b6..b78f993260 100644
--- a/rts/sm/GC.c
+++ b/rts/sm/GC.c
@@ -270,7 +270,7 @@ GarbageCollect (uint32_t collect_gen,
   generation *gen;
   StgWord live_blocks, live_words, par_max_copied, par_balanced_copied,
       gc_spin_spin, gc_spin_yield, mut_spin_spin, mut_spin_yield,
-      any_work, no_work, scav_find_work;
+      any_work, scav_find_work;
 #if defined(THREADED_RTS)
   gc_thread *saved_gct;
 #endif
@@ -593,7 +593,6 @@ GarbageCollect (uint32_t collect_gen,
   mut_spin_spin = 0;
   mut_spin_yield = 0;
   any_work = 0;
-  no_work = 0;
   scav_find_work = 0;
   {
       uint32_t i;
@@ -614,8 +613,6 @@ GarbageCollect (uint32_t collect_gen,
                          RELAXED_LOAD(&thread->scanned) * sizeof(W_));
               debugTrace(DEBUG_gc,"   any_work         %ld",
                          RELAXED_LOAD(&thread->any_work));
-              debugTrace(DEBUG_gc,"   no_work          %ld",
-                         RELAXED_LOAD(&thread->no_work));
               debugTrace(DEBUG_gc,"   scav_find_work %ld",
                          RELAXED_LOAD(&thread->scav_find_work));
 
@@ -627,7 +624,6 @@ GarbageCollect (uint32_t collect_gen,
 #endif
 
               any_work += RELAXED_LOAD(&thread->any_work);
-              no_work += RELAXED_LOAD(&thread->no_work);
               scav_find_work += RELAXED_LOAD(&thread->scav_find_work);
 
               par_max_copied = stg_max(RELAXED_LOAD(&thread->copied), par_max_copied);
@@ -1047,7 +1043,7 @@ GarbageCollect (uint32_t collect_gen,
              N, n_gc_threads, gc_threads,
              par_max_copied, par_balanced_copied,
              gc_spin_spin, gc_spin_yield, mut_spin_spin, mut_spin_yield,
-             any_work, no_work, scav_find_work);
+             any_work, scav_find_work);
 
 #if defined(RTS_USER_SIGNALS)
   if (RtsFlags.MiscFlags.install_signal_handlers) {
@@ -1188,7 +1184,6 @@ freeGcThreads (void)
         closeCondition(&gc_running_cv);
         closeMutex(&gc_running_mutex);
         stgFree (gc_threads);
-
 #else
         for (g = 0; g < RtsFlags.GcFlags.generations; g++)
         {
@@ -1320,7 +1315,6 @@ scavenge_until_all_done (void)
                 traceEventGcWork(gct->cap);
                 continue; // for(;;) loop
             }
-            NONATOMIC_ADD(&gct->no_work, 1);
         }
 #endif
         break; // for(;;) loop
@@ -1808,7 +1802,6 @@ init_gc_thread (gc_thread *t)
     t->copied = 0;
     t->scanned = 0;
     t->any_work = 0;
-    t->no_work = 0;
     t->scav_find_work = 0;
 }
 
diff --git a/rts/sm/GCThread.h b/rts/sm/GCThread.h
index d15189988d..90d15c69c5 100644
--- a/rts/sm/GCThread.h
+++ b/rts/sm/GCThread.h
@@ -182,7 +182,6 @@ typedef struct gc_thread_ {
     W_ copied;
     W_ scanned;
     W_ any_work;
-    W_ no_work;
     W_ scav_find_work;
 
     Time gc_start_cpu;             // thread CPU time
diff --git a/rts/sm/GCUtils.c b/rts/sm/GCUtils.c
index ea7d83ab8f..89a92bc837 100644
--- a/rts/sm/GCUtils.c
+++ b/rts/sm/GCUtils.c
@@ -129,8 +129,7 @@ steal_todo_block (uint32_t g)
     // look for work to steal
     for (n = 0; n < n_gc_threads; n++) {
         if (n == gct->thread_index) continue;
-        q = gc_threads[n]->gens[g].todo_q;
-        bd = stealWSDeque(q);
+        bd = stealWSDeque(gc_threads[n]->gens[g].todo_q);
         if (bd) {
             return bd;
         }