From f9ac60a90ffcaacf576920508431d6fa7f3c92e4 Mon Sep 17 00:00:00 2001
From: daan <daanl@outlook.com>
Date: Fri, 12 Nov 2021 19:03:20 -0800
Subject: [PATCH] suppres eager commit delay for the first 4 threads

---
 include/mimalloc-internal.h | 1 +
 src/init.c                  | 8 ++++++++
 src/segment.c               | 2 +-
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/mimalloc-internal.h b/include/mimalloc-internal.h
index 5c716a79..a2549f7e 100644
--- a/include/mimalloc-internal.h
+++ b/include/mimalloc-internal.h
@@ -63,6 +63,7 @@ static inline uintptr_t _mi_random_shuffle(uintptr_t x);
 extern mi_decl_cache_align mi_stats_t       _mi_stats_main;
 extern mi_decl_cache_align const mi_page_t  _mi_page_empty;
 bool       _mi_is_main_thread(void);
+size_t     _mi_current_thread_count(void);
 bool       _mi_preloading(void);  // true while the C runtime is not ready
 
 // os.c
diff --git a/src/init.c b/src/init.c
index cb9d123f..db3d24ba 100644
--- a/src/init.c
+++ b/src/init.c
@@ -332,6 +332,12 @@ bool _mi_is_main_thread(void) {
   return (_mi_heap_main.thread_id==0 || _mi_heap_main.thread_id == _mi_thread_id());
 }
 
+static _Atomic(uintptr_t) thread_count = ATOMIC_VAR_INIT(1);
+
+size_t  _mi_current_thread_count(void) {
+  return mi_atomic_load_relaxed(&thread_count);
+}
+
 // This is called from the `mi_malloc_generic`
 void mi_thread_init(void) mi_attr_noexcept
 {
@@ -344,6 +350,7 @@ void mi_thread_init(void) mi_attr_noexcept
   if (_mi_heap_init()) return;  // returns true if already initialized
 
   _mi_stat_increase(&_mi_stats_main.threads, 1);
+  mi_atomic_increment_relaxed(&thread_count);
   //_mi_verbose_message("thread init: 0x%zx\n", _mi_thread_id());
 }
 
@@ -352,6 +359,7 @@ void mi_thread_done(void) mi_attr_noexcept {
 }
 
 static void _mi_thread_done(mi_heap_t* heap) {
+  mi_atomic_decrement_relaxed(&thread_count);
   _mi_stat_decrease(&_mi_stats_main.threads, 1);
 
   // check thread-id as on Windows shutdown with FLS the main (exit) thread may call this on thread-local heaps...
diff --git a/src/segment.c b/src/segment.c
index 4c2fa32e..1fffd745 100644
--- a/src/segment.c
+++ b/src/segment.c
@@ -579,7 +579,7 @@ static mi_segment_t* mi_segment_init(mi_segment_t* segment, size_t required, mi_
   mi_assert_internal(segment_size >= required);
 
   // Initialize parameters
-  const bool eager_delayed = (page_kind <= MI_PAGE_MEDIUM && !_mi_is_main_thread() &&
+  const bool eager_delayed = (page_kind <= MI_PAGE_MEDIUM && _mi_current_thread_count() > 4 &&
                               tld->count < (size_t)mi_option_get(mi_option_eager_commit_delay));
   const bool eager  = !eager_delayed && mi_option_is_enabled(mi_option_eager_commit);
   bool commit = eager; // || (page_kind >= MI_PAGE_LARGE);