From 58f62e830fd345f627c3404dd31c7727b99bc685 Mon Sep 17 00:00:00 2001
From: fis <jm.yuan@outlook.com>
Date: Mon, 8 Nov 2021 18:00:25 +0800
Subject: [PATCH] Remove weird set thread.

---
 src/common/threading_utils.h  | 3 +--
 tests/cpp/tree/test_approx.cc | 3 ++-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/common/threading_utils.h b/src/common/threading_utils.h
index fe0008444f5f..da8ddf3c2c6d 100644
--- a/src/common/threading_utils.h
+++ b/src/common/threading_utils.h
@@ -130,8 +130,7 @@ class BlockedSpace2d {
 template <typename Func>
 void ParallelFor2d(const BlockedSpace2d& space, int nthreads, Func func) {
   const size_t num_blocks_in_space = space.Size();
-  nthreads = std::min(nthreads, omp_get_max_threads());
-  nthreads = std::max(nthreads, 1);
+  CHECK_GE(nthreads, 1);
 
   dmlc::OMPException exc;
 #pragma omp parallel num_threads(nthreads)
diff --git a/tests/cpp/tree/test_approx.cc b/tests/cpp/tree/test_approx.cc
index b19e13af43eb..e598069234be 100644
--- a/tests/cpp/tree/test_approx.cc
+++ b/tests/cpp/tree/test_approx.cc
@@ -78,8 +78,9 @@ TEST(Approx, PredictionCache) {
   auto Xy = RandomDataGenerator{n_samples, n_features, 0}.GenerateDMatrix(true);
 
   {
+    omp_set_num_threads(1);
     GenericParameter ctx;
-    ctx.InitAllowUnknown(Args{});
+    ctx.InitAllowUnknown(Args{{"nthread", "8"}});
     std::unique_ptr<TreeUpdater> approx{
         TreeUpdater::Create("grow_global_approx_histmaker", &ctx, ObjInfo{ObjInfo::kRegression})};
     RegTree tree;