Enable properly working core limits on clients and servers,

and determine these dynamically if only one or the other is
specified but both are running on the same host

src/proto/grpc/testing/control.proto

@@ -110,6 +110,7 @@ message ClientConfig {
 
   // Specify the cores we should run the client on, if desired
   repeated int32 core_list = 13;
+  int32 core_limit = 14;
 }
 
 message ClientStatus { ClientStats stats = 1; }
@@ -139,6 +140,7 @@ message ServerConfig {
 
   // Specify the cores we should run the server on, if desired
   repeated int32 core_list = 10;
+  int32 core_limit = 11;
 }
 
 message ServerArgs {
@@ -152,6 +154,14 @@ message ServerStatus {
   ServerStats stats = 1;
   // the port bound by the server
   int32 port = 2;
-  // Number of cores on the server. See gpr_cpu_num_cores.
+  // Number of cores available to the server
   int32 cores = 3;
 }
+
+message CoreRequest {
+}
+
+message CoreResponse {
+  // Number of cores available on the server
+  int32 cores = 1;
+}

src/proto/grpc/testing/services.proto

@@ -62,4 +62,7 @@ service WorkerService {
   // and once the shutdown has finished, the OK status is sent to terminate
   // this RPC.
   rpc RunClient(stream ClientArgs) returns (stream ClientStatus);
+
+  // Just return the core count - unary call
+  rpc CoreCount(CoreRequest) returns (CoreResponse);
 }

test/cpp/qps/driver.cc

@@ -34,6 +34,7 @@
 #include <deque>
 #include <list>
 #include <thread>
+#include <unordered_map>
 #include <vector>
 
 #include <grpc++/channel.h>
@@ -59,7 +60,42 @@ using std::vector;
 
 namespace grpc {
 namespace testing {
-static deque<string> get_hosts(const string& name) {
+static std::string get_host(const std::string &worker) {
+  char *host;
+  char *port;
+
+  gpr_split_host_port(worker.c_str(), &host, &port);
+  string s(host);
+
+  gpr_free(host);
+  gpr_free(port);
+  return s;
+}
+
+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);
+    if (hosts.find(host) == hosts.end()) {
+      auto stub = WorkerService::NewStub(
+          CreateChannel(*it, InsecureChannelCredentials()));
+      grpc::ClientContext ctx;
+      CoreRequest dummy;
+      CoreResponse cores;
+      grpc::Status s = stub->CoreCount(&ctx, dummy, &cores);
+      assert(s.ok());
+      std::deque<int> dq;
+      for (int i=0; i<cores.cores(); i++) {
+        dq.push_back(i);
+      }
+      hosts[host] = dq;
+    }
+  }
+  return hosts;
+}
+
+static deque<string> get_workers(const string& name) {
   char* env = gpr_getenv(name.c_str());
   if (!env) return deque<string>();
 
@@ -105,7 +141,7 @@ struct ClientData {
 
 std::unique_ptr<ScenarioResult> RunScenario(
     const ClientConfig& initial_client_config, size_t num_clients,
-    const ServerConfig& server_config, size_t num_servers, int warmup_seconds,
+    const ServerConfig& initial_server_config, size_t num_servers, int warmup_seconds,
     int benchmark_seconds, int spawn_local_worker_count) {
   // ClientContext allocations (all are destroyed at scope exit)
   list<ClientContext> contexts;
@@ -113,10 +149,10 @@ 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;
+  ServerConfig result_server_config = initial_server_config;
 
   // Get client, server lists
-  auto workers = get_hosts("QPS_WORKERS");
+  auto workers = get_workers("QPS_WORKERS");
   ClientConfig client_config = initial_client_config;
 
   // Spawn some local workers if desired
@@ -143,6 +179,9 @@ std::unique_ptr<ScenarioResult> RunScenario(
     }
   }
 
+  // Setup the hosts and core counts
+  auto hosts_cores = get_hosts_and_cores(workers);
+
   // if num_clients is set to <=0, do dynamic sizing: all workers
   // except for servers are clients
   if (num_clients <= 0) {
@@ -172,18 +211,49 @@ std::unique_ptr<ScenarioResult> RunScenario(
             i);
     servers[i].stub = WorkerService::NewStub(
         CreateChannel(workers[i], InsecureChannelCredentials()));
+
+    ServerConfig server_config = initial_server_config;
+    char* host;
+    char* driver_port;
+    char* cli_target;
+    gpr_split_host_port(workers[i].c_str(), &host, &driver_port);
+    string host_str(host);
+    int server_core_limit = initial_server_config.core_limit();
+    int client_core_limit = initial_client_config.core_limit();
+
+    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];
+      bool match = false;
+      int limit = dq.size();
+      for (size_t cli = 0; cli < num_clients; cli++) {
+        if (host_str == get_host(workers[cli+num_servers])) {
+          limit -= client_core_limit;
+          match = true;
+        }
+      }
+      if (match) {
+        GPR_ASSERT(limit > 0);
+        server_core_limit = limit;
+      }
+    }
+    if (server_core_limit > 0) {
+      auto& dq = hosts_cores[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());
+        dq.pop_front();
+      }
+    }
+
     ServerArgs args;
-    result_server_config = server_config;
     *args.mutable_setup() = server_config;
     servers[i].stream =
         servers[i].stub->RunServer(runsc::AllocContext(&contexts, deadline));
     GPR_ASSERT(servers[i].stream->Write(args));
     ServerStatus init_status;
     GPR_ASSERT(servers[i].stream->Read(&init_status));
-    char* host;
-    char* driver_port;
-    char* cli_target;
-    gpr_split_host_port(workers[i].c_str(), &host, &driver_port);
     gpr_join_host_port(&cli_target, host, init_status.port());
     client_config.add_server_targets(cli_target);
     gpr_free(host);
@@ -191,19 +261,49 @@ std::unique_ptr<ScenarioResult> RunScenario(
     gpr_free(cli_target);
   }
 
+  // Targets are all set by now
+  result_client_config = client_config;
   // Start clients
   using runsc::ClientData;
   // clients is array rather than std::vector to avoid gcc-4.4 issues
   // where class contained in std::vector must have a copy constructor
   auto* clients = new ClientData[num_clients];
   for (size_t i = 0; i < num_clients; i++) {
+    const auto& worker = workers[i + num_servers];
     gpr_log(GPR_INFO, "Starting client on %s (worker #%d)",
-            workers[i + num_servers].c_str(), i + num_servers);
+            worker.c_str(), i + num_servers);
     clients[i].stub = WorkerService::NewStub(
-        CreateChannel(workers[i + num_servers], InsecureChannelCredentials()));
+        CreateChannel(worker, InsecureChannelCredentials()));
+    ClientConfig per_client_config = client_config;
+
+    int server_core_limit = initial_server_config.core_limit();
+    int client_core_limit = initial_client_config.core_limit();
+    if ((server_core_limit > 0) || (client_core_limit > 0)) {
+      auto& dq = hosts_cores[get_host(worker)];
+      if (client_core_limit == 0) {
+        // limit client cores if it matches a server host
+        bool match = false;
+        int limit = dq.size();
+        for (size_t srv = 0; srv < num_servers; srv++) {
+          if (get_host(worker) == get_host(workers[srv])) {
+            match = true;
+          }
+        }
+        if (match) {
+          client_core_limit = limit;
+        }
+      }
+      if (client_core_limit > 0) {
+        GPR_ASSERT(dq.size() >= static_cast<size_t>(client_core_limit));
+        for (int core=0; core < client_core_limit; core++) {
+          per_client_config.add_core_list(dq.front());
+          dq.pop_front();
+        }
+      }
+    }
+
     ClientArgs args;
-    result_client_config = client_config;
-    *args.mutable_setup() = client_config;
+    *args.mutable_setup() = per_client_config;
     clients[i].stream =
         clients[i].stub->RunClient(runsc::AllocContext(&contexts, deadline));
     GPR_ASSERT(clients[i].stream->Write(args));

test/cpp/qps/qps_driver.cc

@@ -51,8 +51,7 @@ DEFINE_int32(local_workers, 0, "Number of local workers to start");
 // Server config
 DEFINE_int32(async_server_threads, 1, "Number of threads for async servers");
 DEFINE_string(server_type, "SYNC_SERVER", "Server type");
-// TODO (vpai): Automatically generate the core list to avoid breakage
-DEFINE_string(server_core_list, "", "Comma-separated list of cores for server");
+DEFINE_int32(server_core_limit, -1, "Limit on server cores to use");
 
 // Client config
 DEFINE_string(rpc_type, "UNARY", "Type of RPC: UNARY or STREAMING");
@@ -75,8 +74,7 @@ DEFINE_double(determ_load, -1.0, "Deterministic offered load (qps)");
 DEFINE_double(pareto_base, -1.0, "Pareto base interarrival time (us)");
 DEFINE_double(pareto_alpha, -1.0, "Pareto alpha value");
 
-// TODO (vpai): Automatically generate the core list to avoid breakage
-DEFINE_string(client_core_list, "", "Comma-separated list of cores for client");
+DEFINE_int32(client_core_limit, -1, "Limit on client cores to use");
 
 DEFINE_bool(secure_test, false, "Run a secure test");
 
@@ -91,22 +89,6 @@ using grpc::testing::SecurityParams;
 namespace grpc {
 namespace testing {
 
-static std::vector<int> IntParse(const std::string& s) {
-  size_t pos = 0;
-  std::vector<int> res;
-  while (pos < s.size()) {
-    size_t comma = s.find(',', pos);
-    if (comma == std::string::npos) {
-      res.push_back(std::stoi(s.substr(pos)));
-      break;
-    } else {
-      res.push_back(std::stoi(s.substr(pos, comma - pos), nullptr));
-      pos = comma + 1;
-    }
-  }
-  return res;
-}
-
 static void QpsDriver() {
   RpcType rpc_type;
   GPR_ASSERT(RpcType_Parse(FLAGS_rpc_type, &rpc_type));
@@ -170,22 +152,16 @@ static void QpsDriver() {
   client_config.mutable_histogram_params()->set_max_possible(
       Histogram::default_max_possible());
 
-  if (FLAGS_client_core_list.size() > 0) {
-    auto v = IntParse(FLAGS_client_core_list);
-    for (size_t i = 0; i < v.size(); i++) {
-      client_config.add_core_list(v[i]);
-    }
+  if (FLAGS_client_core_limit > 0) {
+    client_config.set_core_limit(FLAGS_client_core_limit);
   }
 
   ServerConfig server_config;
   server_config.set_server_type(server_type);
   server_config.set_async_server_threads(FLAGS_async_server_threads);
 
-  if (FLAGS_server_core_list.size() > 0) {
-    auto v = IntParse(FLAGS_server_core_list);
-    for (size_t i = 0; i < v.size(); i++) {
-      server_config.add_core_list(v[i]);
-    }
+  if (FLAGS_server_core_limit > 0) {
+    server_config.set_core_limit(FLAGS_server_core_limit);
   }
 
   if (FLAGS_secure_test) {

test/cpp/qps/qps_worker.cc

@@ -47,6 +47,7 @@
 #include <grpc++/server_builder.h>
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
+#include <grpc/support/cpu.h>
 #include <grpc/support/histogram.h>
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
@@ -133,6 +134,12 @@ class WorkerServiceImpl GRPC_FINAL : public WorkerService::Service {
     return ret;
   }
 
+  Status CoreCount(ServerContext *ctx, const CoreRequest*,
+                   CoreResponse* resp) GRPC_OVERRIDE {
+    resp->set_cores(gpr_cpu_num_cores());
+    return Status::OK;
+  }
+
  private:
   // Protect against multiple clients using this worker at once.
   class InstanceGuard {