1 files changed, 117 insertions, 25 deletions

diff --git a/test/cpp/qps/qps_json_driver.cc b/test/cpp/qps/qps_json_driver.cc
index 1524ebbc38..31b5917fb7 100644
--- a/test/cpp/qps/qps_json_driver.cc
+++ b/test/cpp/qps/qps_json_driver.cc
@@ -49,10 +49,111 @@ DEFINE_string(scenarios_file, "",
 DEFINE_string(scenarios_json, "",
               "JSON string containing an array of Scenario objects");
 DEFINE_bool(quit, false, "Quit the workers");
+DEFINE_string(search_param, "",
+              "The parameter, whose value is to be searched for to achieve "
+              "targeted cpu load. For now, we have 'offered_load'. Later, "
+              "'num_channels', 'num_outstanding_requests', etc. shall be "
+              "added.");
+DEFINE_double(
+    initial_search_value, 0.0,
+    "initial parameter value to start the search with (i.e. lower bound)");
+DEFINE_double(targeted_cpu_load, 70.0,
+              "Targeted cpu load (unit: %, range [0,100])");
+DEFINE_double(stride, 1,
+              "Defines each stride of the search. The larger the stride is, "
+              "the coarser the result will be, but will also be faster.");
+DEFINE_double(error_tolerance, 0.01,
+              "Defines threshold for stopping the search. When current search "
+              "range is narrower than the error_tolerance computed range, we "
+              "stop the search.");
 
 namespace grpc {
 namespace testing {
 
+static std::unique_ptr<ScenarioResult> RunAndReport(const Scenario& scenario,
+                                                    bool* success) {
+  std::cerr << "RUNNING SCENARIO: " << scenario.name() << "\n";
+  auto result =
+      RunScenario(scenario.client_config(), scenario.num_clients(),
+                  scenario.server_config(), scenario.num_servers(),
+                  scenario.warmup_seconds(), scenario.benchmark_seconds(),
+                  scenario.spawn_local_worker_count());
+
+  // Amend the result with scenario config. Eventually we should adjust
+  // RunScenario contract so we don't need to touch the result here.
+  result->mutable_scenario()->CopyFrom(scenario);
+
+  GetReporter()->ReportQPS(*result);
+  GetReporter()->ReportQPSPerCore(*result);
+  GetReporter()->ReportLatency(*result);
+  GetReporter()->ReportTimes(*result);
+  GetReporter()->ReportCpuUsage(*result);
+
+  for (int i = 0; *success && i < result->client_success_size(); i++) {
+    *success = result->client_success(i);
+  }
+  for (int i = 0; *success && i < result->server_success_size(); i++) {
+    *success = result->server_success(i);
+  }
+
+  return result;
+}
+
+static double GetCpuLoad(Scenario* scenario, double offered_load,
+                         bool* success) {
+  scenario->mutable_client_config()
+      ->mutable_load_params()
+      ->mutable_poisson()
+      ->set_offered_load(offered_load);
+  auto result = RunAndReport(*scenario, success);
+  return result->summary().server_cpu_usage();
+}
+
+static double BinarySearch(Scenario* scenario, double targeted_cpu_load,
+                           double low, double high, bool* success) {
+  while (low <= high * (1 - FLAGS_error_tolerance)) {
+    double mid = low + (high - low) / 2;
+    double current_cpu_load = GetCpuLoad(scenario, mid, success);
+    gpr_log(GPR_DEBUG, "Binary Search: current_offered_load %.0f", mid);
+    if (!*success) {
+      gpr_log(GPR_ERROR, "Client/Server Failure");
+      break;
+    }
+    if (targeted_cpu_load <= current_cpu_load) {
+      high = mid - FLAGS_stride;
+    } else {
+      low = mid + FLAGS_stride;
+    }
+  }
+
+  return low;
+}
+
+static double SearchOfferedLoad(double initial_offered_load,
+                                double targeted_cpu_load, Scenario* scenario,
+                                bool* success) {
+  std::cerr << "RUNNING SCENARIO: " << scenario->name() << "\n";
+  double current_offered_load = initial_offered_load;
+  double current_cpu_load = GetCpuLoad(scenario, current_offered_load, success);
+  if (current_cpu_load > targeted_cpu_load) {
+    gpr_log(GPR_ERROR, "Initial offered load too high");
+    return -1;
+  }
+
+  while (*success && (current_cpu_load < targeted_cpu_load)) {
+    current_offered_load *= 2;
+    current_cpu_load = GetCpuLoad(scenario, current_offered_load, success);
+    gpr_log(GPR_DEBUG, "Binary Search: current_offered_load  %.0f",
+            current_offered_load);
+  }
+
+  double targeted_offered_load =
+      BinarySearch(scenario, targeted_cpu_load, current_offered_load / 2,
+                   current_offered_load, success);
+
+  return targeted_offered_load;
+}
+
 static bool QpsDriver() {
   grpc::string json;
 
@@ -68,11 +169,11 @@ static bool QpsDriver() {
 
   if (scfile) {
     // Read the json data from disk
-    FILE *json_file = fopen(FLAGS_scenarios_file.c_str(), "r");
+    FILE* json_file = fopen(FLAGS_scenarios_file.c_str(), "r");
     GPR_ASSERT(json_file != NULL);
     fseek(json_file, 0, SEEK_END);
     long len = ftell(json_file);
-    char *data = new char[len];
+    char* data = new char[len];
     fseek(json_file, 0, SEEK_SET);
     GPR_ASSERT(len == (long)fread(data, 1, len, json_file));
     fclose(json_file);
@@ -93,28 +194,19 @@ static bool QpsDriver() {
   GPR_ASSERT(scenarios.scenarios_size() > 0);
 
   for (int i = 0; i < scenarios.scenarios_size(); i++) {
-    const Scenario &scenario = scenarios.scenarios(i);
-    std::cerr << "RUNNING SCENARIO: " << scenario.name() << "\n";
-    auto result =
-        RunScenario(scenario.client_config(), scenario.num_clients(),
-                    scenario.server_config(), scenario.num_servers(),
-                    scenario.warmup_seconds(), scenario.benchmark_seconds(),
-                    scenario.spawn_local_worker_count());
-
-    // Amend the result with scenario config. Eventually we should adjust
-    // RunScenario contract so we don't need to touch the result here.
-    result->mutable_scenario()->CopyFrom(scenario);
-
-    GetReporter()->ReportQPS(*result);
-    GetReporter()->ReportQPSPerCore(*result);
-    GetReporter()->ReportLatency(*result);
-    GetReporter()->ReportTimes(*result);
-
-    for (int i = 0; success && i < result->client_success_size(); i++) {
-      success = result->client_success(i);
-    }
-    for (int i = 0; success && i < result->server_success_size(); i++) {
-      success = result->server_success(i);
+    if (FLAGS_search_param == "") {
+      const Scenario& scenario = scenarios.scenarios(i);
+      RunAndReport(scenario, &success);
+    } else {
+      if (FLAGS_search_param == "offered_load") {
+        Scenario* scenario = scenarios.mutable_scenarios(i);
+        double targeted_offered_load =
+            SearchOfferedLoad(FLAGS_initial_search_value,
+                              FLAGS_targeted_cpu_load, scenario, &success);
+        gpr_log(GPR_INFO, "targeted_offered_load %f", targeted_offered_load);
+      } else {
+        gpr_log(GPR_ERROR, "Unimplemented search param");
+      }
     }
   }
   return success;
@@ -123,7 +215,7 @@ static bool QpsDriver() {
 }  // namespace testing
 }  // namespace grpc
 
-int main(int argc, char **argv) {
+int main(int argc, char** argv) {
   grpc::testing::InitBenchmark(&argc, &argv, true);
 
   bool ok = grpc::testing::QpsDriver();