From b824f7476f36ae6e1dfd3eca49db5f985a62b4b3 Mon Sep 17 00:00:00 2001
From: Nikolai Maas <nikolai.maas@kit.edu>
Date: Mon, 25 Nov 2024 15:44:17 +0100
Subject: [PATCH] fix

---
 CMakeLists.txt                         | 10 ++++-----
 cmake/modules/CheckThreadPinning.cmake | 29 ++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 5 deletions(-)
 create mode 100644 cmake/modules/CheckThreadPinning.cmake

diff --git a/CMakeLists.txt b/CMakeLists.txt
index de9f648b5..8cc3f1dd3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -155,7 +155,7 @@ endif()
 
 
 #################################################################
-## Platform-specific includes, which interact with options     ##
+## Platform compatibility checks, which interact with options  ##
 #################################################################
 
 if(UNIX)
@@ -166,10 +166,10 @@ if(UNIX)
   if(NOT KAHYPAR_HEADERS_AVAILABLE)
     message(FATAL_ERROR "The following system headers are required, but some are not available: ${KAHYPAR_REQUIRED_HEADERS}")
   endif()
-  set(KAHYPAR_THREAD_PINNING_HEADERS "sched.h")
-  check_include_files("${KAHYPAR_THREAD_PINNING_HEADERS}" KAHYPAR_THREAD_PINNING_IS_POSSIBLE LANGUAGE CXX)
-  if(KAHYPAR_ENABLE_THREAD_PINNING AND NOT KAHYPAR_THREAD_PINNING_IS_POSSIBLE)
-    message(WARNING "Thread pinning disabled since header is not available: ${KAHYPAR_THREAD_PINNING_HEADERS}")
+
+  include(CheckThreadPinning)
+  if(KAHYPAR_ENABLE_THREAD_PINNING AND NOT THREAD_PINNING_WORKS)
+    message(WARNING "Thread pinning disabled since required system APIs are not available.")
     set(KAHYPAR_ENABLE_THREAD_PINNING FALSE)
   endif()
 elseif(NOT WIN32)
diff --git a/cmake/modules/CheckThreadPinning.cmake b/cmake/modules/CheckThreadPinning.cmake
new file mode 100644
index 000000000..24431bdce
--- /dev/null
+++ b/cmake/modules/CheckThreadPinning.cmake
@@ -0,0 +1,29 @@
+# Check if the required APIs for thread pinning are available
+
+set(THREAD_PINNING_WORKS FALSE)
+if(UNIX)
+	# Check if sched_getcpu/sched_setaffinity are available
+	check_include_files("schedx.h" HEADER_AVAILABLE LANGUAGE CXX)
+	if(${HEADER_AVAILABLE})
+		# we need to actually check the available symbols
+		include(CheckSourceCompiles)
+		check_source_compiles(CXX
+		"#include <sched.h>
+		int main() {
+			int cpu_id = sched_getcpu();
+			int num_cpus = 4;
+			const size_t size = CPU_ALLOC_SIZE(num_cpus);
+			cpu_set_t mask;
+			CPU_ZERO(&mask);
+			CPU_SET(cpu_id, &mask);
+			int err = sched_setaffinity(0, size, &mask);
+			return 0;
+		}"
+		EXAMPLE_COMPILES)
+		if(${EXAMPLE_COMPILES})
+			set(THREAD_PINNING_WORKS TRUE)
+		endif()
+	endif()
+elseif(WIN32)
+	set(THREAD_PINNING_WORKS TRUE)
+endif()