From e55237c505750ff4793c818d57429aaabc23f277 Mon Sep 17 00:00:00 2001
From: Anirudh Subramanian <anirudh2290@apache.org>
Date: Mon, 3 Dec 2018 13:50:12 -0800
Subject: [PATCH] Revert "Manually track num_max_thread (#12380)" (#13501)

This reverts commit 75410210e07a5fab5e044348aee276d578d5857e.
---
 src/engine/openmp.cc | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/engine/openmp.cc b/src/engine/openmp.cc
index 64899b09660e..8fe3939892d2 100644
--- a/src/engine/openmp.cc
+++ b/src/engine/openmp.cc
@@ -73,14 +73,18 @@ void OpenMP::set_reserve_cores(int cores) {
   CHECK_GE(cores, 0);
   reserve_cores_ = cores;
 #ifdef _OPENMP
-  omp_thread_max_ = std::max(omp_thread_max_ - reserve_cores_, 1);
+  if (reserve_cores_ >= omp_thread_max_) {
+    omp_set_num_threads(1);
+  } else {
+    omp_set_num_threads(omp_thread_max_ - reserve_cores_);
+  }
 #endif
 }
 
 int OpenMP::GetRecommendedOMPThreadCount(bool exclude_reserved) const {
 #ifdef _OPENMP
   if (omp_num_threads_set_in_environment_) {
-    return omp_thread_max_;
+    return omp_get_max_threads();
   }
   if (enabled_) {
     int thread_count = omp_get_max_threads();
@@ -97,8 +101,10 @@ int OpenMP::GetRecommendedOMPThreadCount(bool exclude_reserved) const {
     }
     return omp_thread_max_;
   }
-#endif
   return 1;
+#else
+  return 1;
+#endif
 }
 
 OpenMP *__init_omp__ = OpenMP::Get();