QUIC - histograms to measure the time spent to read QUIC sever

net/quic/quic_crypto_client_stream.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/quic_crypto_client_stream.h"
 
+#include "base/metrics/histogram.h"
 #include "net/base/completion_callback.h"
 #include "net/base/net_errors.h"
 #include "net/quic/crypto/crypto_protocol.h"
 #include "net/quic/crypto/crypto_utils.h"
 #include "net/quic/crypto/null_encrypter.h"
 #include "net/quic/crypto/proof_verifier.h"
 #include "net/quic/crypto/proof_verifier_chromium.h"
 #include "net/quic/crypto/quic_server_info.h"
 #include "net/quic/quic_protocol.h"
 #include "net/quic/quic_session.h"
@@ skipping 398 matching lines @@
 }
 
 int QuicCryptoClientStream::DoLoadQuicServerInfo(
     QuicCryptoClientConfig::CachedState* cached) {
   next_state_ = STATE_SEND_CHLO;
   QuicServerInfo* quic_server_info = cached->quic_server_info();
   if (!quic_server_info) {
     return OK;
   }
 
+  read_start_time_ = base::TimeTicks::Now();
   generation_counter_ = cached->generation_counter();
   next_state_ = STATE_LOAD_QUIC_SERVER_INFO_COMPLETE;
 
-  // TODO(rtenneti): If multiple tabs load the same URL, all requests except for
-  // the first request send InchoateClientHello. Fix the code to handle multiple
-  // requests. A possible solution is to wait for the first request to finish
-  // and use the data from the disk cache for all requests.
+  // TODO(rtenneti): Use host:port to access QUIC server information from disk
+  // cache. If multiple tabs load URLs with same hostname but different
+  // ports, all requests except for the first request send InchoateClientHello.
+  // Fix the code to handle multiple requests. A possible solution is to wait
+  // for the first request to finish and use the data from the disk cache for
+  // all requests.
   // We may need to call quic_server_info->Persist later.
   // quic_server_info->Persist requires quic_server_info to be ready, so we
   // always call WaitForDataReady, even though we might have initialized
   // |cached| config from the cached state for a canonical hostname.
   int rv = quic_server_info->WaitForDataReady(
       base::Bind(&QuicCryptoClientStream::OnIOComplete,
                  weak_factory_.GetWeakPtr()));
 
   if (rv != ERR_IO_PENDING) {
     disk_cache_load_result_ = rv;
@@ skipping 12 matching lines @@
     QuicCryptoClientConfig::CachedState* cached) {
   next_state_ = STATE_SEND_CHLO;
 
   // If someone else already saved a server config, we don't want to overwrite
   // it. Also, if someone else saved a server config and then cleared it (so
   // cached->IsEmpty() is true), we still want to load from QuicServerInfo.
   if (!cached->IsEmpty()) {
     return;
   }
 
+  UMA_HISTOGRAM_TIMES("Net.QuicServerInfo.DiskCacheReadTime",
+                      base::TimeTicks::Now() - read_start_time_);
+
   if (disk_cache_load_result_ != OK || !cached->LoadQuicServerInfo(
           session()->connection()->clock()->WallNow())) {
     // It is ok to proceed to STATE_SEND_CHLO when we cannot load QuicServerInfo
     // from the disk cache.
     DCHECK(cached->IsEmpty());
     DVLOG(1) << "Empty server_config";
     return;
   }
 
   ProofVerifier* verifier = crypto_config_->proof_verifier();
   if (!verifier) {
     // If no verifier is set then we don't check the certificates.
     cached->SetProofValid();
   } else if (!cached->signature().empty()) {
     next_state_ = STATE_VERIFY_PROOF;
   }
 }
 
 }  // namespace net