Limits only 16 new QUIC connections can be opened per epoll event.

net/tools/quic/quic_server.cc

Index: net/tools/quic/quic_server.cc
diff --git a/net/tools/quic/quic_server.cc b/net/tools/quic/quic_server.cc
index 11eba67ef3877b627c168e8cf3abb35eb25a6f3a..dadb49b381b3a7c35410e24581e0c65b0ee0d8fe 100644
--- a/net/tools/quic/quic_server.cc
+++ b/net/tools/quic/quic_server.cc
@@ -48,6 +48,8 @@ const char kSourceAddressTokenSecret[] = "secret";
 
 }  // namespace
 
+const size_t kNumSessionsToCreatePerSocketEvent = 16;
+
 QuicServer::QuicServer(std::unique_ptr<ProofSource> proof_source)
     : QuicServer(std::move(proof_source),
                  QuicConfig(),
@@ -177,6 +179,12 @@ void QuicServer::OnEvent(int fd, EpollEvent* event) {
 
   if (event->in_events & EPOLLIN) {
     DVLOG(1) << "EPOLLIN";
+
+    if (FLAGS_quic_limit_num_new_sessions_per_epoll_loop &&
+        FLAGS_quic_buffer_packet_till_chlo) {
+      dispatcher_->ProcessBufferedChlos(kNumSessionsToCreatePerSocketEvent);
+    }
+
     bool more_to_read = true;
     while (more_to_read) {
       more_to_read = packet_reader_->ReadAndDispatchPackets(
@@ -184,6 +192,12 @@ void QuicServer::OnEvent(int fd, EpollEvent* event) {
           QuicEpollClock(&epoll_server_), dispatcher_.get(),
           overflow_supported_ ? &packets_dropped_ : nullptr);
     }
+
+    if (FLAGS_quic_limit_num_new_sessions_per_epoll_loop &&
+        FLAGS_quic_buffer_packet_till_chlo && dispatcher_->HasChlosBuffered()) {
+      // Register EPOLLIN event to consume buffered CHLO(s).
+      event->out_ready_mask |= EPOLLIN;
+    }
   }
   if (event->in_events & EPOLLOUT) {
     dispatcher_->OnCanWrite();