Revert "Fix GC pacing problem exacerbated by mark-delay (#3331)"

This reverts commit aded4b5.

Author: mshinwell

runtime/major_gc.c

@@ -755,27 +755,6 @@ static void update_major_slice_work(intnat howmuch,
   atomic_fetch_add (&work_counter, dom_st->major_work_done_between_slices);
   dom_st->major_work_done_between_slices = 0;
   atomic_fetch_add (&alloc_counter, new_work);
-
-  /* If the work_counter is falling far behind the alloc_counter,
-   * artificially catch up some of the difference. This is a band-aid
-   * for general GC pacing problems revealed by the mark-delay changes
-   * (see comments on ocaml/ocaml PR #13580): when we rework the
-   * pacing this should go away. */
-  int64_t pending = diffmod(atomic_load(&alloc_counter),
-                             atomic_load(&work_counter));
-  if (pending > (int64_t)total_cycle_work * 2) {
-    intnat catchup = pending - total_cycle_work;
-    caml_gc_message(0x40,
-                    "work counter %"ARCH_INTNAT_PRINTF_FORMAT"u falling behind "
-                    "alloc counter %"ARCH_INTNAT_PRINTF_FORMAT"u by more than "
-                    "twice a total cycle's work %"ARCH_INTNAT_PRINTF_FORMAT"d; "
-                    "catching up by %"ARCH_INTNAT_PRINTF_FORMAT "d\n",
-                    atomic_load(&work_counter),
-                    atomic_load(&alloc_counter),
-                    total_cycle_work, catchup);
-    atomic_fetch_add (&work_counter, catchup);
-  }
-
   if (howmuch == AUTO_TRIGGERED_MAJOR_SLICE ||
       howmuch == GC_CALCULATE_MAJOR_SLICE) {
     dom_st->slice_target = atomic_load (&alloc_counter);