rometsch · December 22, 2022 14:38 · Dec 22, 2022
diff --git a/numa.py b/numa.py
@@ -0,0 +1,41 @@
+import os
+import re
+
+def get_numa_nodes():
+    """Return the numa topology of the system.
+    
+    Data is extracted from /sys/devices/system/cpu.
+    The numa nodes on the system are the keys of the dictionary.
+    Each value is a list of tuples which themselves represent physical cores.
+    Each tuples contains the id of the threads belonging to the physical core.
+    Without hyperthreading, each tuple contains one id, with hyperthreading each tuple contains two keys.
+
+    Returns:
+        dict: Topology of the numa nodes.
+    """
+
+    path = "/sys/devices/system/cpu"
+
+    cpus = [d for d in os.listdir(path) if re.match("cpu\d+", d) is not None]
+
+    nodes = {}
+
+    for cpu in cpus:
+        cpu_path = os.path.join(path, cpu)
+        cpu_node = [s for s in os.listdir(cpu_path) if re.match("node\d+",s)][0]
+        with open(os.path.join(cpu_path, "topology", "thread_siblings_list"), "r") as infile:
+            threads = sorted(infile.read().strip().split(","))
+        threads = tuple(threads)
+        try:
+            nodes[cpu_node].add(threads)
+        except KeyError:
+            nodes[cpu_node] = set()
+            nodes[cpu_node].add(threads)
+
+    for key in nodes:
+        nodes[key] = sorted(nodes[key])
+
+    return nodes
+
+if __name__=="__main__":
+    print(get_numa_nodes())
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