[PERF] Add interleaved memory allocation to NUMA module (#30800)

csrc/cpu/utils.cpp

@@ -24,6 +24,8 @@ std::string init_cpu_threads_env(const std::string& cpu_ids) {
 #ifndef VLLM_NUMA_DISABLED
 std::string init_cpu_threads_env(const std::string& cpu_ids) {
   bitmask* omp_cpu_mask = numa_parse_cpustring_all(cpu_ids.c_str());
+  TORCH_CHECK(omp_cpu_mask != nullptr,
+              "Failed to parse CPU string: " + cpu_ids);
   TORCH_CHECK(omp_cpu_mask->size > 0);
   std::vector<int> omp_cpu_ids;
   omp_cpu_ids.reserve(omp_cpu_mask->size);
@@ -44,20 +46,12 @@ std::string init_cpu_threads_env(const std::string& cpu_ids) {
 
   // Memory node binding
   if (numa_available() != -1) {
-    int mem_node_id = numa_node_of_cpu(omp_cpu_ids.front());
     std::set<int> node_ids;
     for (const auto& cpu_id : omp_cpu_ids) {
       int node_id = numa_node_of_cpu(cpu_id);
       if (node_id != -1) {
         node_ids.insert(node_id);
       }
-      if (node_id != mem_node_id) {
-        TORCH_WARN("CPU ", cpu_id, " is on NUMA node ", node_id, ", but CPU ",
-                   omp_cpu_ids.front(), " is on NUMA node ", mem_node_id,
-                   ". All CPUs should be on the same NUMA node for optimal "
-                   "performance. Memory will be bound to NUMA node ",
-                   mem_node_id, ".");
-      }
     }
     // Concatenate all node_ids into a single comma-separated string
     if (!node_ids.empty()) {
@@ -70,7 +64,7 @@ std::string init_cpu_threads_env(const std::string& cpu_ids) {
       }
 
       bitmask* mask = numa_parse_nodestring(node_ids_str.c_str());
-      bitmask* src_mask = numa_get_membind();
+      bitmask* src_mask = numa_get_mems_allowed();
 
       int pid = getpid();
 
@@ -83,14 +77,45 @@ std::string init_cpu_threads_env(const std::string& cpu_ids) {
                      std::to_string(errno));
         }
 
-        // restrict memory allocation node.
+        // Restrict memory allocation to the selected NUMA node(s).
+        // Enhances memory locality for the threads bound to those NUMA CPUs.
+        if (node_ids.size() > 1) {
+          errno = 0;
+          numa_set_interleave_mask(mask);
+          if (errno != 0) {
+            TORCH_WARN("numa_set_interleave_mask failed. errno: " +
+                       std::to_string(errno));
+          } else {
+            TORCH_WARN(
+                "NUMA binding: Using INTERLEAVE policy for memory "
+                "allocation across multiple NUMA nodes (nodes: " +
+                node_ids_str +
+                "). Memory allocations will be "
+                "interleaved across the specified NUMA nodes.");
+          }
+        } else {
+          errno = 0;
           numa_set_membind(mask);
+          if (errno != 0) {
+            TORCH_WARN("numa_set_membind failed. errno: " +
+                       std::to_string(errno));
+          } else {
+            TORCH_WARN(
+                "NUMA binding: Using MEMBIND policy for memory "
+                "allocation on the NUMA nodes (" +
+                node_ids_str +
+                "). Memory allocations will be "
+                "strictly bound to these NUMA nodes.");
+          }
+        }
+
         numa_set_strict(1);
 
         numa_free_nodemask(mask);
         numa_free_nodemask(src_mask);
       } else {
-        TORCH_WARN("numa_parse_nodestring or numa_get_membind failed. errno: " +
+        TORCH_WARN(
+            "numa_parse_nodestring or numa_get_run_node_mask failed. errno: " +
             std::to_string(errno));
       }
     }