Address reviewer comments regarding const and shortage of comments

test/cpp/qps/driver.cc

@@ -65,7 +65,7 @@ static std::string get_host(const std::string& worker) {
   char* port;
 
   gpr_split_host_port(worker.c_str(), &host, &port);
-  string s(host);
+  const string s(host);
 
   gpr_free(host);
   gpr_free(port);
@@ -76,7 +76,7 @@ static std::unordered_map<string, std::deque<int>> get_hosts_and_cores(
     const deque<string>& workers) {
   std::unordered_map<string, std::deque<int>> hosts;
   for (auto it = workers.begin(); it != workers.end(); it++) {
-    string host = get_host(*it);
+    const string host = get_host(*it);
     if (hosts.find(host) == hosts.end()) {
       auto stub = WorkerService::NewStub(
           CreateChannel(*it, InsecureChannelCredentials()));
@@ -149,7 +149,7 @@ std::unique_ptr<ScenarioResult> RunScenario(
   // To be added to the result, containing the final configuration used for
   // client and config (including host, etc.)
   ClientConfig result_client_config;
-  ServerConfig result_server_config = initial_server_config;
+  const ServerConfig result_server_config = initial_server_config;
 
   // Get client, server lists
   auto workers = get_workers("QPS_WORKERS");
@@ -224,7 +224,7 @@ std::unique_ptr<ScenarioResult> RunScenario(
     if (server_core_limit == 0 && client_core_limit > 0) {
       // In this case, limit the server cores if it matches the
       // same host as one or more clients
-      const auto& dq = hosts_cores[host_str];
+      const auto& dq = hosts_cores.at(host_str);
       bool match = false;
       int limit = dq.size();
       for (size_t cli = 0; cli < num_clients; cli++) {
@@ -239,7 +239,7 @@ std::unique_ptr<ScenarioResult> RunScenario(
       }
     }
     if (server_core_limit > 0) {
-      auto& dq = hosts_cores[host_str];
+      auto& dq = hosts_cores.at(host_str);
       GPR_ASSERT(dq.size() >= static_cast<size_t>(server_core_limit));
       for (int core = 0; core < server_core_limit; core++) {
         server_config.add_core_list(dq.front());

test/cpp/qps/limit_cores.cc

@@ -47,12 +47,12 @@ namespace testing {
 #endif
 #include <sched.h>
 int LimitCores(const int *cores, int cores_size) {
-  int num_cores = gpr_cpu_num_cores();
+  const int num_cores = gpr_cpu_num_cores();
   int cores_set = 0;
 
   cpu_set_t *cpup = CPU_ALLOC(num_cores);
   GPR_ASSERT(cpup);
-  size_t size = CPU_ALLOC_SIZE(num_cores);
+  const size_t size = CPU_ALLOC_SIZE(num_cores);
   CPU_ZERO_S(size, cpup);
 
   if (cores_size > 0) {

test/cpp/qps/limit_cores.h

@@ -38,9 +38,12 @@
 
 namespace grpc {
 namespace testing {
-// LimitCores takes array and size arguments (instead of vector) for more direct
-// conversion from repeated field of protobuf. Use a cores_size of 0 to remove
-// existing limits (from an empty repeated field)
+/// LimitCores: allow this worker to only run on the cores specified in the
+/// array \a cores, which is of length \a cores_size.
+///
+/// LimitCores takes array and size arguments (instead of vector) for direct
+/// conversion from repeated field of protobuf. Use a cores_size of 0 to remove
+/// existing limits (from an empty repeated field)
 int LimitCores(const int *cores, int cores_size);
 }  // namespace testing
 }  // namespace grpc