diff --git a/benchmarks/util.cpp b/benchmarks/util.cpp
index 92e8243..ec74147 100644
--- a/benchmarks/util.cpp
+++ b/benchmarks/util.cpp
@@ -71,36 +71,17 @@
 
 #else
 
-bool LockToCPU(long cpu_to_lock) {
+bool LockToCPU(int cpu_to_lock) {
   cpu_set_t cpuset;
 
   CPU_ZERO(&cpuset);
-  if (sched_getaffinity(0, sizeof(cpuset), &cpuset) != 0) {
-    perror("sched_getaffinity failed");
-    return false;
-  }
-
-  if (cpu_to_lock < 0) {
-    // Lock to the last active core we find.
-    for (int i = 0; i < CPU_SETSIZE; i++) {
-      if (CPU_ISSET(i, &cpuset)) {
-        cpu_to_lock = i;
-      }
-    }
-  } else if (!CPU_ISSET(cpu_to_lock, &cpuset)) {
-    printf("Cpu %ld does not exist.\n", cpu_to_lock);
-    return false;
-  }
-
-  if (cpu_to_lock < 0) {
-    printf("Cannot find any valid cpu to lock.\n");
-    return false;
-  }
-
-  CPU_ZERO(&cpuset);
   CPU_SET(cpu_to_lock, &cpuset);
   if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) {
-    perror("sched_setaffinity failed");
+    if (errno == EINVAL) {
+      printf("Invalid cpu %d\n", cpu_to_lock);
+    } else {
+      perror("sched_setaffinity failed");
+    }
     return false;
   }