--- a/modules/libpref/init/all.js
+++ b/modules/libpref/init/all.js
@@ -1355,16 +1355,22 @@ pref("network.http.enforce-framing.soft"
 
 // default values for FTP
 // in a DSCP environment this should be 40 (0x28, or AF11), per RFC-4594,
 // Section 4.8 "High-Throughput Data Service Class", and 80 (0x50, or AF22)
 // per Section 4.7 "Low-Latency Data Service Class".
 pref("network.ftp.data.qos", 0);
 pref("network.ftp.control.qos", 0);
 
+// If this pref is false only one xpcom event will be served per poll
+// iteration. This is the original behavior.
+// If it is true multiple events will be served.
+pref("network.sts.serve_multiple_events_per_poll_iteration", true);
+// The max time to spend on xpcom events between two polls in ms.
+pref("network.sts.max_time_for_events_between_two_polls", 100);
 // </http>
 
 // 2147483647 == PR_INT32_MAX == ~2 GB
 pref("network.websocket.max-message-size", 2147483647);
 
 // Should we automatically follow http 3xx redirects during handshake
 pref("network.websocket.auto-follow-http-redirects", false);
 

--- a/netwerk/base/nsSocketTransportService2.cpp
+++ b/netwerk/base/nsSocketTransportService2.cpp
@@ -14,16 +14,17 @@
 #include "NetworkActivityMonitor.h"
 #include "nsIObserverService.h"
 #include "mozilla/Services.h"
 #include "mozilla/Preferences.h"
 #include "mozilla/Likely.h"
 #include "mozilla/PublicSSL.h"
 #include "mozilla/ChaosMode.h"
 #include "mozilla/PodOperations.h"
+#include "mozilla/TimeStamp.h"
 #include "nsThreadUtils.h"
 #include "nsIFile.h"
 
 using namespace mozilla;
 using namespace mozilla::net;
 
 #if defined(PR_LOGGING)
 PRLogModuleInfo *gSocketTransportLog = nullptr;
@@ -35,16 +36,18 @@ PRThread                 *gSocketThread 
 #define SEND_BUFFER_PREF "network.tcp.sendbuffer"
 #define KEEPALIVE_ENABLED_PREF "network.tcp.keepalive.enabled"
 #define KEEPALIVE_IDLE_TIME_PREF "network.tcp.keepalive.idle_time"
 #define KEEPALIVE_RETRY_INTERVAL_PREF "network.tcp.keepalive.retry_interval"
 #define KEEPALIVE_PROBE_COUNT_PREF "network.tcp.keepalive.probe_count"
 #define SOCKET_LIMIT_TARGET 550U
 #define SOCKET_LIMIT_MIN     50U
 #define BLIP_INTERVAL_PREF "network.activity.blipIntervalMilliseconds"
+#define SERVE_MULTIPLE_EVENTS_PREF "network.sts.serve_multiple_events_per_poll_iteration"
+#define MAX_TIME_BETWEEN_TWO_POLLS "network.sts.max_time_for_events_between_two_polls"
 
 uint32_t nsSocketTransportService::gMaxCount;
 PRCallOnceType nsSocketTransportService::gMaxCountInitOnce;
 
 //-----------------------------------------------------------------------------
 // ctor/dtor (called on the main/UI thread by the service manager)
 
 nsSocketTransportService::nsSocketTransportService()
@@ -62,16 +65,19 @@ nsSocketTransportService::nsSocketTransp
     , mIdleCount(0)
     , mSentBytesCount(0)
     , mReceivedBytesCount(0)
     , mSendBufferSize(0)
     , mKeepaliveIdleTimeS(600)
     , mKeepaliveRetryIntervalS(1)
     , mKeepaliveProbeCount(kDefaultTCPKeepCount)
     , mKeepaliveEnabledPref(false)
+    , mServeMultipleEventsPerPollIter(true)
+    , mServingPendingQueue(false)
+    , mMaxTimePerPollIter(100)
     , mProbedMaxCount(false)
 {
 #if defined(PR_LOGGING)
     gSocketTransportLog = PR_NewLogModule("nsSocketTransport");
 #endif
 
     NS_ASSERTION(NS_IsMainThread(), "wrong thread");
 
@@ -476,16 +482,18 @@ nsSocketTransportService::Init()
 
     nsCOMPtr<nsIPrefBranch> tmpPrefService = do_GetService(NS_PREFSERVICE_CONTRACTID);
     if (tmpPrefService) {
         tmpPrefService->AddObserver(SEND_BUFFER_PREF, this, false);
         tmpPrefService->AddObserver(KEEPALIVE_ENABLED_PREF, this, false);
         tmpPrefService->AddObserver(KEEPALIVE_IDLE_TIME_PREF, this, false);
         tmpPrefService->AddObserver(KEEPALIVE_RETRY_INTERVAL_PREF, this, false);
         tmpPrefService->AddObserver(KEEPALIVE_PROBE_COUNT_PREF, this, false);
+        tmpPrefService->AddObserver(SERVE_MULTIPLE_EVENTS_PREF, this, false);
+        tmpPrefService->AddObserver(MAX_TIME_BETWEEN_TWO_POLLS, this, false);
     }
     UpdatePrefs();
 
     nsCOMPtr<nsIObserverService> obsSvc = services::GetObserverService();
     if (obsSvc) {
         obsSvc->AddObserver(this, "profile-initial-state", false);
         obsSvc->AddObserver(this, "last-pb-context-exited", false);
     }
@@ -681,16 +689,22 @@ nsSocketTransportService::OnProcessNextE
 NS_IMETHODIMP
 nsSocketTransportService::AfterProcessNextEvent(nsIThreadInternal* thread,
                                                 uint32_t depth,
                                                 bool eventWasProcessed)
 {
     return NS_OK;
 }
 
+void
+nsSocketTransportService::MarkTheLastElementOfPendingQueue()
+{
+    mServingPendingQueue = false;
+}
+
 #ifdef MOZ_NUWA_PROCESS
 #include "ipc/Nuwa.h"
 #endif
 
 NS_IMETHODIMP
 nsSocketTransportService::Run()
 {
     PR_SetCurrentThreadName("Socket Thread");
@@ -725,25 +739,49 @@ nsSocketTransportService::Run()
     for (;;) {
         bool pendingEvents = false;
         thread->HasPendingEvents(&pendingEvents);
 
         do {
             // If there are pending events for this thread then
             // DoPollIteration() should service the network without blocking.
             DoPollIteration(!pendingEvents);
-            
+
             // If nothing was pending before the poll, it might be now
-            if (!pendingEvents)
+            if (!pendingEvents) {
                 thread->HasPendingEvents(&pendingEvents);
+            }
 
             if (pendingEvents) {
-                NS_ProcessNextEvent(thread);
-                pendingEvents = false;
-                thread->HasPendingEvents(&pendingEvents);
+                if (mServeMultipleEventsPerPollIter) {
+                    if (!mServingPendingQueue) {
+                        nsresult rv = Dispatch(NS_NewRunnableMethod(this,
+                            &nsSocketTransportService::MarkTheLastElementOfPendingQueue),
+                            nsIEventTarget::DISPATCH_NORMAL);
+                        if (NS_FAILED(rv)) {
+                            NS_WARNING("Could not dispatch a new event on the "
+                                       "socket thread.");
+                        } else {
+                            mServingPendingQueue = true;
+                        }
+                    }
+                    TimeStamp eventQueueStart = TimeStamp::NowLoRes();
+                    do {
+                        NS_ProcessNextEvent(thread);
+                        pendingEvents = false;
+                        thread->HasPendingEvents(&pendingEvents);
+                    } while (pendingEvents && mServingPendingQueue &&
+                             ((TimeStamp::NowLoRes() -
+                               eventQueueStart).ToMilliseconds() <
+                              mMaxTimePerPollIter));
+                } else {
+                    NS_ProcessNextEvent(thread);
+                    pendingEvents = false;
+                    thread->HasPendingEvents(&pendingEvents);
+                }
             }
         } while (pendingEvents);
 
         bool goingOffline = false;
         // now that our event queue is empty, check to see if we should exit
         {
             MutexAutoLock lock(mLock);
             if (mShuttingDown)
@@ -977,16 +1015,30 @@ nsSocketTransportService::UpdatePrefs()
                                            1, kMaxTCPKeepCount);
         bool keepaliveEnabled = false;
         rv = tmpPrefService->GetBoolPref(KEEPALIVE_ENABLED_PREF,
                                          &keepaliveEnabled);
         if (NS_SUCCEEDED(rv) && keepaliveEnabled != mKeepaliveEnabledPref) {
             mKeepaliveEnabledPref = keepaliveEnabled;
             OnKeepaliveEnabledPrefChange();
         }
+
+        bool serveMultiplePref = false;
+        rv = tmpPrefService->GetBoolPref(SERVE_MULTIPLE_EVENTS_PREF,
+                                         &serveMultiplePref);
+        if (NS_SUCCEEDED(rv)) {
+            mServeMultipleEventsPerPollIter = serveMultiplePref;
+        }
+
+        int32_t maxTimePref;
+        rv = tmpPrefService->GetIntPref(MAX_TIME_BETWEEN_TWO_POLLS,
+                                        &maxTimePref);
+        if (NS_SUCCEEDED(rv) && maxTimePref >= 0) {
+            mMaxTimePerPollIter = maxTimePref;
+        }
     }
     
     return NS_OK;
 }
 
 void
 nsSocketTransportService::OnKeepaliveEnabledPrefChange()
 {

--- a/netwerk/base/nsSocketTransportService2.h
+++ b/netwerk/base/nsSocketTransportService2.h
@@ -12,16 +12,17 @@
 #include "nsEventQueue.h"
 #include "nsCOMPtr.h"
 #include "prinrval.h"
 #include "prlog.h"
 #include "prinit.h"
 #include "nsIObserver.h"
 #include "mozilla/Mutex.h"
 #include "mozilla/net/DashboardTypes.h"
+#include "mozilla/Atomics.h"
 
 class nsASocketHandler;
 struct PRPollDesc;
 
 //-----------------------------------------------------------------------------
 
 #if defined(PR_LOGGING)
 //
@@ -212,30 +213,36 @@ private:
     int32_t     mKeepaliveIdleTimeS;
     // Number of seconds between retries should keepalive pings fail.
     int32_t     mKeepaliveRetryIntervalS;
     // Number of keepalive probes to send.
     int32_t     mKeepaliveProbeCount;
     // True if TCP keepalive is enabled globally.
     bool        mKeepaliveEnabledPref;
 
+    bool                   mServeMultipleEventsPerPollIter;
+    mozilla::Atomic<bool>  mServingPendingQueue;
+    int32_t                mMaxTimePerPollIter;
+
     void OnKeepaliveEnabledPrefChange();
     void NotifyKeepaliveEnabledPrefChange(SocketContext *sock);
 
     // Socket thread only for dynamically adjusting max socket size
 #if defined(XP_WIN)
     void ProbeMaxCount();
 #endif
     bool mProbedMaxCount;
 
     void AnalyzeConnection(nsTArray<mozilla::net::SocketInfo> *data,
                            SocketContext *context, bool aActive);
 
     void ClosePrivateConnections();
     void DetachSocketWithGuard(bool aGuardLocals,
                                SocketContext *socketList,
                                int32_t index);
+
+    void MarkTheLastElementOfPendingQueue();
 };
 
 extern nsSocketTransportService *gSocketTransportService;
 extern PRThread                 *gSocketThread;
 
 #endif // !nsSocketTransportService_h__