Bug Fix - Fix numa error on grace cpu in gpu-copy (#658)

The current GPU Copy BW Performance fails on Nvidia Grace systems. This
is due to the memory only numa node and thus the numa_run_on_node fails
for such nodes and halts completely.

This fix checks for the presence of assigned CPU cores for the numa
node, on checking if it has no cpu cores assigned, it skips that
specific node during the args creation and continues.

superbench/benchmarks/micro_benchmarks/gpu_copy_performance/gpu_copy.cu

@@ -3,9 +3,9 @@
 
 // GPU copy benchmark tests dtoh/htod/dtod data transfer bandwidth by GPU SM/DMA.
 
+#include <cerrno> // errno
 #include <cstdio>
 #include <cstring>
-#include <string>
 #include <vector>
 
 #include <getopt.h>
@@ -313,6 +313,25 @@ int SetGpu(int gpu_id) {
     return 0;
 }
 
+// Check if its NUMA node has CPUs.
+bool HasCPUsForNumaNode(int node) {
+    struct bitmask *bm = numa_allocate_cpumask();
+
+    int numa_err = numa_node_to_cpus(node, bm);
+    if (numa_err != 0) {
+        fprintf(stderr, "HasCPUsForNumaNode::numa_node_to_cpus error on node: %d, code: %d, message: %s\n", node, errno,
+                strerror(errno));
+
+        numa_bitmask_free(bm);
+        return false; // On error
+    }
+
+    // Check if any CPU is assigned to the NUMA node, has_cpus is false for mem only numa nodes
+    bool has_cpus = (numa_bitmask_weight(bm) > 0);
+    numa_free_cpumask(bm);
+    return has_cpus;
+}
+
 #if defined(__HIP_PLATFORM_AMD__)
 bool UseFineGrained(const SubBenchArgs &args) {
     return args.is_src_dev_gpu && args.is_dst_dev_gpu && args.src_gpu_id != args.dst_gpu_id;
@@ -1134,6 +1153,12 @@ int main(int argc, char **argv) {
     // Scan all NUMA nodes
     for (int i = 0; i < numa_count; i++) {
         args.numa_id = i;
+
+        // Avoid numa nodes without CPUS(eg. Nvidia Grace systems have memory only numa node)
+        if (!HasCPUsForNumaNode(args.numa_id)) {
+            continue;
+        }
+
         // Scan all GPUs
         for (int j = 0; j < gpu_count; j++) {
             // Host-to-device benchmark