h2load: Add --rps option

src/h2load.cc

@@ -117,6 +117,7 @@ Config::~Config() {
 bool Config::is_rate_mode() const { return (this->rate != 0); }
 bool Config::is_timing_based_mode() const { return (this->duration > 0); }
 bool Config::has_base_uri() const { return (!this->base_uri.empty()); }
+bool Config::rps_enabled() const { return this->rps > 0.0; }
 Config config;
 
 namespace {
@@ -286,6 +287,51 @@ void warmup_timeout_cb(struct ev_loop *loop, ev_timer *w, int revents) {
 }
 } // namespace
 
+namespace {
+void rps_cb(struct ev_loop *loop, ev_timer *w, int revents) {
+  auto client = static_cast<Client *>(w->data);
+  auto &session = client->session;
+
+  assert(!config.timing_script);
+
+  if (client->req_left == 0) {
+    ev_timer_stop(loop, w);
+    return;
+  }
+
+  auto now = ev_now(loop);
+  auto d = now - client->rps_duration_started;
+  auto n = static_cast<size_t>(round(d * config.rps));
+  client->rps_req_pending += n;
+  client->rps_duration_started = now - d + static_cast<double>(n) / config.rps;
+
+  if (client->rps_req_pending == 0) {
+    return;
+  }
+
+  auto nreq = session->max_concurrent_streams() - client->rps_req_inflight;
+  if (nreq == 0) {
+    return;
+  }
+
+  nreq = config.is_timing_based_mode() ? std::max(nreq, client->req_left)
+                                       : std::min(nreq, client->req_left);
+  nreq = std::min(nreq, client->rps_req_pending);
+
+  client->rps_req_inflight += nreq;
+  client->rps_req_pending -= nreq;
+
+  for (; nreq > 0; --nreq) {
+    if (client->submit_request() != 0) {
+      client->process_request_failure();
+      break;
+    }
+  }
+
+  client->signal_write();
+}
+} // namespace
+
 namespace {
 // Called when an a connection has been inactive for a set period of time
 // or a fixed amount of time after all requests have been made on a
@@ -374,7 +420,10 @@ Client::Client(uint32_t id, Worker *worker, size_t req_todo)
       id(id),
       fd(-1),
       new_connection_requested(false),
-      final(false) {
+      final(false),
+      rps_duration_started(0),
+      rps_req_pending(0),
+      rps_req_inflight(0) {
   if (req_todo == 0) { // this means infinite number of requests are to be made
     // This ensures that number of requests are unbounded
     // Just a positive number is fine, we chose the first positive number
@@ -396,6 +445,9 @@ Client::Client(uint32_t id, Worker *worker, size_t req_todo)
 
   ev_timer_init(&request_timeout_watcher, client_request_timeout_cb, 0., 0.);
   request_timeout_watcher.data = this;
+
+  ev_timer_init(&rps_watcher, rps_cb, 0., 0.);
+  rps_watcher.data = this;
 }
 
 Client::~Client() {
@@ -552,6 +604,7 @@ void Client::disconnect() {
 
   ev_timer_stop(worker->loop, &conn_inactivity_watcher);
   ev_timer_stop(worker->loop, &conn_active_watcher);
+  ev_timer_stop(worker->loop, &rps_watcher);
   ev_timer_stop(worker->loop, &request_timeout_watcher);
   streams.clear();
   session.reset();
@@ -866,8 +919,18 @@ void Client::on_stream_close(int32_t stream_id, bool success, bool final) {
       if (!ev_is_active(&request_timeout_watcher)) {
         ev_feed_event(worker->loop, &request_timeout_watcher, EV_TIMER);
       }
-    } else if (submit_request() != 0) {
-      process_request_failure();
+    } else if (!config.rps_enabled()) {
+      if (submit_request() != 0) {
+        process_request_failure();
+      }
+    } else if (rps_req_pending) {
+      --rps_req_pending;
+      if (submit_request() != 0) {
+        process_request_failure();
+      }
+    } else {
+      assert(rps_req_inflight);
+      --rps_req_inflight;
     }
   }
 }
@@ -962,10 +1025,25 @@ int Client::connection_made() {
 
   record_connect_time();
 
-  if (!config.timing_script) {
+  if (config.rps_enabled()) {
+    rps_watcher.repeat = std::max(0.01, 1. / config.rps);
+    ev_timer_again(worker->loop, &rps_watcher);
+    rps_duration_started = ev_now(worker->loop);
+  }
+
+  if (config.rps_enabled()) {
+    assert(req_left);
+
+    ++rps_req_inflight;
+
+    if (submit_request() != 0) {
+      process_request_failure();
+    }
+  } else if (!config.timing_script) {
     auto nreq = config.is_timing_based_mode()
                     ? std::max(req_left, session->max_concurrent_streams())
                     : std::min(req_left, session->max_concurrent_streams());
+
     for (; nreq > 0; --nreq) {
       if (submit_request() != 0) {
         process_request_failure();
@@ -1943,7 +2021,8 @@ void print_help(std::ostream &out) {
               port defined in  the first URI are  used solely.  Values
               contained  in  other  URIs,  if  present,  are  ignored.
               Definition of a  base URI overrides all  scheme, host or
-              port values.
+              port   values.   --timing-script-file   and  --rps   are
+              mutually exclusive.
   -B, --base-uri=(<URI>|unix:<PATH>)
               Specify URI from which the scheme, host and port will be
               used  for  all requests.   The  base  URI overrides  all
@@ -1988,6 +2067,8 @@ void print_help(std::ostream &out) {
   --connect-to=<HOST>[:<PORT>]
               Host and port to connect  instead of using the authority
               in <URI>.
+  --rps=<N>   Specify request  per second for each  client.  --rps and
+              --timing-script-file are mutually exclusive.
   -v, --verbose
               Output debug information.
   --version   Display version information and exit.
@@ -2047,6 +2128,7 @@ int main(int argc, char **argv) {
         {"warm-up-time", required_argument, &flag, 9},
         {"log-file", required_argument, &flag, 10},
         {"connect-to", required_argument, &flag, 11},
+        {"rps", required_argument, &flag, 12},
         {nullptr, 0, nullptr, 0}};
     int option_index = 0;
     auto c = getopt_long(argc, argv,
@@ -2286,6 +2368,17 @@ int main(int argc, char **argv) {
         config.connect_to_port = port;
         break;
       }
+      case 12: {
+        char *end;
+        auto v = std::strtod(optarg, &end);
+        if (end == optarg || *end != '\0' || !std::isfinite(v) ||
+            1. / v < 1e-6) {
+          std::cerr << "--rps: Invalid value " << optarg << std::endl;
+          exit(EXIT_FAILURE);
+        }
+        config.rps = v;
+        break;
+      }
       }
       break;
     default:
@@ -2376,6 +2469,12 @@ int main(int argc, char **argv) {
     exit(EXIT_FAILURE);
   }
 
+  if (config.timing_script && config.rps_enabled()) {
+    std::cerr << "--timing-script-file, --rps: they are mutually exclusive."
+              << std::endl;
+    exit(EXIT_FAILURE);
+  }
+
   if (config.nreqs == 0 && !config.is_timing_based_mode()) {
     std::cerr << "-n: the number of requests must be strictly greater than 0 "
                  "if timing-based test is not being run."

src/h2load.h

@@ -114,13 +114,16 @@ struct Config {
   // list of supported NPN/ALPN protocol strings in the order of
   // preference.
   std::vector<std::string> npn_list;
+  // The number of request per second for each client.
+  double rps;
 
   Config();
   ~Config();
 
   bool is_rate_mode() const;
   bool is_timing_based_mode() const;
   bool has_base_uri() const;
+  bool rps_enabled() const;
 };
 
 struct RequestStat {
@@ -336,6 +339,20 @@ struct Client {
   // true if the current connection will be closed, and no more new
   // request cannot be processed.
   bool final;
+  // rps_watcher is a timer to invoke callback periodically to
+  // generate a new request.
+  ev_timer rps_watcher;
+  // The timestamp that starts the period which contributes to the
+  // next request generation.
+  ev_tstamp rps_duration_started;
+  // The number of requests allowed by rps, but limited by stream
+  // concurrency.
+  size_t rps_req_pending;
+  // The number of in-flight streams.  req_inflight has similar value
+  // but it only measures requests made during Phase::MAIN_DURATION.
+  // rps_req_inflight measures the number of requests in all phases,
+  // and it is only used if --rps is given.
+  size_t rps_req_inflight;
 
   enum { ERR_CONNECT_FAIL = -100 };