Narrow the instrumentation to track jank in HostResolverImpl.

net/dns/host_resolver_impl.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/dns/host_resolver_impl.h"
 
 #if defined(OS_WIN)
 #include <Winsock2.h>
 #elif defined(OS_POSIX)
 #include <netdb.h>
@@ skipping 167 matching lines @@
         !hostname.compare(hostname.size() - kSuffixLen, kSuffixLen, kSuffix);
   }
   return hostname.size() > kSuffixLenTrimmed &&
       !hostname.compare(hostname.size() - kSuffixLenTrimmed, kSuffixLenTrimmed,
                         kSuffix, kSuffixLenTrimmed);
 }
 
 // Attempts to connect a UDP socket to |dest|:53.
 bool IsGloballyReachable(const IPAddressNumber& dest,
                          const BoundNetLog& net_log) {
+  // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
+  tracked_objects::ScopedTracker tracking_profile_1(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455942 IsGloballyReachable (create udp socket)"));
+
   scoped_ptr<DatagramClientSocket> socket(
       ClientSocketFactory::GetDefaultFactory()->CreateDatagramClientSocket(
           DatagramSocket::DEFAULT_BIND,
           RandIntCallback(),
           net_log.net_log(),
           net_log.source()));
+  // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
+  tracked_objects::ScopedTracker tracking_profile_2(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 IsGloballyReachable (connect)"));
   int rv = socket->Connect(IPEndPoint(dest, 53));
   if (rv != OK)
     return false;
+  tracked_objects::ScopedTracker tracking_profile_3(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455942 IsGloballyReachable (get local addr)"));
   IPEndPoint endpoint;
   rv = socket->GetLocalAddress(&endpoint);
   if (rv != OK)
     return false;
+  tracked_objects::ScopedTracker tracking_profile_4(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION(
+          "455942 IsGloballyReachable (remainder)"));
   DCHECK_EQ(ADDRESS_FAMILY_IPV6, endpoint.GetFamily());
   const IPAddressNumber& address = endpoint.address();
   bool is_link_local = (address[0] == 0xFE) && ((address[1] & 0xC0) == 0x80);
   if (is_link_local)
     return false;
   const uint8 kTeredoPrefix[] = { 0x20, 0x01, 0, 0 };
   bool is_teredo = std::equal(kTeredoPrefix,
                               kTeredoPrefix + arraysize(kTeredoPrefix),
                               address.begin());
   if (is_teredo)
@@ skipping 1669 matching lines @@
   DCHECK(CalledOnValidThread());
   DCHECK_EQ(false, callback.is_null());
 
   // Check that the caller supplied a valid hostname to resolve.
   std::string labeled_hostname;
   if (!DNSDomainFromDot(info.hostname(), &labeled_hostname))
     return ERR_NAME_NOT_RESOLVED;
 
   LogStartRequest(source_net_log, info);
 
+  tracked_objects::ScopedTracker tracking_profile_1a(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 1a"));
+
   IPAddressNumber ip_number;
   IPAddressNumber* ip_number_ptr = nullptr;
   if (ParseIPLiteralToNumber(info.hostname(), &ip_number))
     ip_number_ptr = &ip_number;
 
+  tracked_objects::ScopedTracker tracking_profile_1b(
+      FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 1b"));
+
   // Build a key that identifies the request in the cache and in the
   // outstanding jobs map.
   Key key = GetEffectiveKeyForRequest(info, ip_number_ptr, source_net_log);
 
   // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
   tracked_objects::ScopedTracker tracking_profile_2(
       FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 2"));
 
   int rv = ResolveHelper(key, info, ip_number_ptr, addresses, source_net_log);
   if (rv != ERR_DNS_CACHE_MISS) {
     LogFinishRequest(source_net_log, info, rv);
     RecordTotalTime(HaveDnsConfig(), info.is_speculative(), base::TimeDelta());
     return rv;
   }
 
-  // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
-  tracked_objects::ScopedTracker tracking_profile_3(
-      FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 3"));
-
   // Next we need to attach our request to a "job". This job is responsible for
   // calling "getaddrinfo(hostname)" on a worker thread.
 
   JobMap::iterator jobit = jobs_.find(key);
   Job* job;
   if (jobit == jobs_.end()) {
-    // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
-    tracked_objects::ScopedTracker tracking_profile_4(
-        FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 4"));
     job =
         new Job(weak_ptr_factory_.GetWeakPtr(), key, priority, source_net_log);
     job->Schedule(false);
 
-    // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
-    tracked_objects::ScopedTracker tracking_profile_5(
-        FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 5"));
-
     // Check for queue overflow.
     if (dispatcher_->num_queued_jobs() > max_queued_jobs_) {
       Job* evicted = static_cast<Job*>(dispatcher_->EvictOldestLowest());
       DCHECK(evicted);
       evicted->OnEvicted();  // Deletes |evicted|.
       if (evicted == job) {
         rv = ERR_HOST_RESOLVER_QUEUE_TOO_LARGE;
         LogFinishRequest(source_net_log, info, rv);
         return rv;
       }
     }
     jobs_.insert(jobit, std::make_pair(key, job));
   } else {
     job = jobit->second;
   }
 
-  // TODO(eroman): Remove ScopedTracker below once crbug.com/455942 is fixed.
-  tracked_objects::ScopedTracker tracking_profile_6(
-      FROM_HERE_WITH_EXPLICIT_FUNCTION("455942 HostResolverImpl::Resolve 6"));
-
   // Can't complete synchronously. Create and attach request.
   scoped_ptr<Request> req(new Request(
       source_net_log, info, priority, callback, addresses));
   if (out_req)
     *out_req = reinterpret_cast<RequestHandle>(req.get());
 
   job->AddRequest(req.Pass());
   // Completion happens during Job::CompleteRequests().
   return ERR_IO_PENDING;
 }
@@ skipping 450 matching lines @@
     dns_client_->SetConfig(dns_config);
     num_dns_failures_ = 0;
     if (dns_client_->GetConfig())
       UMA_HISTOGRAM_BOOLEAN("AsyncDNS.DnsClientEnabled", true);
   }
 
   AbortDnsTasks();
 }
 
 }  // namespace net