From 3442950d26aa590032488b3cf0af3d834c1e1d05 Mon Sep 17 00:00:00 2001
From: Jiaming Yuan <jm.yuan@outlook.com>
Date: Thu, 18 Jul 2024 18:31:15 +0800
Subject: [PATCH] Drop support for CUDA legacy stream.

---
 CMakeLists.txt    | 1 -
 cmake/Utils.cmake | 8 ++------
 2 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f7cf8a6cfa87..034d52164ad2 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -71,7 +71,6 @@ option(HIDE_CXX_SYMBOLS "Build shared library and hide all C++ symbols" OFF)
 option(KEEP_BUILD_ARTIFACTS_IN_BINARY_DIR "Output build artifacts in CMake binary dir" OFF)
 ## CUDA
 option(USE_CUDA  "Build with GPU acceleration" OFF)
-option(USE_PER_THREAD_DEFAULT_STREAM "Build with per-thread default stream" ON)
 option(USE_NCCL  "Build with NCCL to enable distributed GPU support." OFF)
 # This is specifically designed for PyPI binary release and should be disabled for most of the cases.
 option(USE_DLOPEN_NCCL "Whether to load nccl dynamically." OFF)
diff --git a/cmake/Utils.cmake b/cmake/Utils.cmake
index 9563ec3076b2..266cf29b38b2 100644
--- a/cmake/Utils.cmake
+++ b/cmake/Utils.cmake
@@ -80,12 +80,8 @@ function(xgboost_set_cuda_flags target)
     $<$<COMPILE_LANGUAGE:CUDA>:--expt-extended-lambda>
     $<$<COMPILE_LANGUAGE:CUDA>:--expt-relaxed-constexpr>
     $<$<COMPILE_LANGUAGE:CUDA>:-Xcompiler=${OpenMP_CXX_FLAGS}>
-    $<$<COMPILE_LANGUAGE:CUDA>:-Xfatbin=-compress-all>)
-
-  if(USE_PER_THREAD_DEFAULT_STREAM)
-    target_compile_options(${target} PRIVATE
-            $<$<COMPILE_LANGUAGE:CUDA>:--default-stream per-thread>)
-  endif()
+    $<$<COMPILE_LANGUAGE:CUDA>:-Xfatbin=-compress-all>
+    $<$<COMPILE_LANGUAGE:CUDA>:--default-stream per-thread>)
 
   if(FORCE_COLORED_OUTPUT)
     if(FORCE_COLORED_OUTPUT AND (CMAKE_GENERATOR STREQUAL "Ninja") AND