Test for reverting back to 1.8 GC heuristics (#51661)

The 1.10 GC heuristics introduced in
#50144 have been a source of
concerning issues such as
#50705 and
#51601. The PR also doesn't
correctly implement the paper on which it's based, as discussed in
#51498.

Test whether the 1.8 GC heuristics are a viable option.

src/gc-debug.c

@@ -953,29 +953,6 @@ void gc_time_sweep_pause(uint64_t gc_end_t, int64_t actual_allocd,
                    jl_ns2ms(gc_postmark_end - gc_premark_end),
                    sweep_full ? "full" : "quick", -gc_num.allocd / 1024);
 }
-
-void gc_time_summary(int sweep_full, uint64_t start, uint64_t end,
-                     uint64_t freed, uint64_t live, uint64_t interval,
-                     uint64_t pause, uint64_t ttsp, uint64_t mark,
-                     uint64_t sweep)
-{
-    if (sweep_full > 0)
-        jl_safe_printf("TS: %" PRIu64 " Major collection: estimate freed = %" PRIu64
-                       " live = %" PRIu64 "m new interval = %" PRIu64
-                       "m time = %" PRIu64 "ms ttsp = %" PRIu64 "us mark time = %"
-                       PRIu64 "ms sweep time = %" PRIu64 "ms \n",
-                       end, freed, live/1024/1024,
-                       interval/1024/1024, pause/1000000, ttsp,
-                       mark/1000000,sweep/1000000);
-    else
-        jl_safe_printf("TS: %" PRIu64 " Minor collection: estimate freed = %" PRIu64
-                       " live = %" PRIu64 "m new interval = %" PRIu64 "m pause time = %"
-                       PRIu64 "ms ttsp = %" PRIu64 "us mark time = %" PRIu64
-                       "ms sweep time = %" PRIu64 "ms \n",
-                       end, freed, live/1024/1024,
-                       interval/1024/1024, pause/1000000, ttsp,
-                       mark/1000000,sweep/1000000);
-}
 #endif
 
 void jl_gc_debug_init(void)
@@ -1219,7 +1196,7 @@ JL_DLLEXPORT void jl_enable_gc_logging(int enable) {
     gc_logging_enabled = enable;
 }
 
-void _report_gc_finished(uint64_t pause, uint64_t freed, int full, int recollect, int64_t live_bytes) JL_NOTSAFEPOINT {
+void _report_gc_finished(uint64_t pause, uint64_t freed, int full, int recollect) JL_NOTSAFEPOINT {
     if (!gc_logging_enabled) {
         return;
     }
@@ -1228,16 +1205,6 @@ void _report_gc_finished(uint64_t pause, uint64_t freed, int full, int recollect
         full ? "full" : "incr",
         recollect ? "recollect" : ""
     );
-
-    jl_safe_printf("Heap stats: bytes_mapped %.2f MB, bytes_resident %.2f MB,\nheap_size %.2f MB, heap_target %.2f MB, Fragmentation %.3f\n",
-        jl_atomic_load_relaxed(&gc_heap_stats.bytes_mapped)/(double)(1<<20),
-        jl_atomic_load_relaxed(&gc_heap_stats.bytes_resident)/(double)(1<<20),
-        // live_bytes/(double)(1<<20), live byes tracking is not accurate.
-        jl_atomic_load_relaxed(&gc_heap_stats.heap_size)/(double)(1<<20),
-        jl_atomic_load_relaxed(&gc_heap_stats.heap_target)/(double)(1<<20),
-        (double)live_bytes/(double)jl_atomic_load_relaxed(&gc_heap_stats.heap_size)
-    );
-    // Should fragmentation use bytes_resident instead of heap_size?
 }
 
 #ifdef __cplusplus

src/gc-pages.c

@@ -52,8 +52,6 @@ char *jl_gc_try_alloc_pages_(int pg_cnt) JL_NOTSAFEPOINT
         // round data pointer up to the nearest gc_page_data-aligned
         // boundary if mmap didn't already do so.
         mem = (char*)gc_page_data(mem + GC_PAGE_SZ - 1);
-    jl_atomic_fetch_add_relaxed(&gc_heap_stats.bytes_mapped, pages_sz);
-    jl_atomic_fetch_add_relaxed(&gc_heap_stats.bytes_resident, pages_sz);
     return mem;
 }
 
@@ -117,7 +115,6 @@ NOINLINE jl_gc_pagemeta_t *jl_gc_alloc_page(void) JL_NOTSAFEPOINT
     // try to get page from `pool_freed`
     meta = pop_lf_page_metadata_back(&global_page_pool_freed);
     if (meta != NULL) {
-        jl_atomic_fetch_add_relaxed(&gc_heap_stats.bytes_resident, GC_PAGE_SZ);
         gc_alloc_map_set(meta->data, GC_PAGE_ALLOCATED);
         goto exit;
     }
@@ -191,7 +188,6 @@ void jl_gc_free_page(jl_gc_pagemeta_t *pg) JL_NOTSAFEPOINT
     madvise(p, decommit_size, MADV_DONTNEED);
 #endif
     msan_unpoison(p, decommit_size);
-    jl_atomic_fetch_add_relaxed(&gc_heap_stats.bytes_resident, -decommit_size);
 }
 
 #ifdef __cplusplus