Bug 1570932 - Add telemetry about how often we observe network change events, r=dragana

Differential Revision: https://phabricator.services.mozilla.com/D44215

--HG--
extra : moz-landing-system : lando

netwerk/system/linux/nsNetworkLinkService.cpp

@@ -9,6 +9,7 @@
 #include "nsNetworkLinkService.h"
 #include "nsString.h"
 #include "mozilla/Logging.h"
+#include "mozilla/Telemetry.h"
 
 #include "mozilla/StaticPrefs_network.h"
 #include "mozilla/Services.h"
@@ -108,6 +109,13 @@ nsresult nsNetworkLinkService::Shutdown() {
 
 void nsNetworkLinkService::OnNetworkChanged() {
   if (StaticPrefs::network_notify_changed()) {
+    if (!mNetworkChangeTime.IsNull()) {
+      mozilla::Telemetry::AccumulateTimeDelta(
+          mozilla::Telemetry::NETWORK_TIME_BETWEEN_NETWORK_CHANGE_EVENTS,
+          mNetworkChangeTime);
+    }
+    mNetworkChangeTime = TimeStamp::Now();
+
     RefPtr<nsNetworkLinkService> self = this;
     NS_DispatchToMainThread(NS_NewRunnableFunction(
         "nsNetworkLinkService::OnNetworkChanged",

netwerk/system/linux/nsNetworkLinkService.h

@@ -11,6 +11,7 @@
 #include "../netlink/NetlinkService.h"
 #include "mozilla/RefPtr.h"
 #include "mozilla/Atomics.h"
+#include "mozilla/TimeStamp.h"
 
 class nsNetworkLinkService : public nsINetworkLinkService,
                              public nsIObserver,
@@ -40,6 +41,9 @@ class nsNetworkLinkService : public nsINetworkLinkService,
   mozilla::Atomic<bool, mozilla::Relaxed> mStatusIsKnown;
 
   RefPtr<mozilla::net::NetlinkService> mNetlinkSvc;
+
+  // Time stamp of last NS_NETWORK_LINK_DATA_CHANGED event
+  mozilla::TimeStamp mNetworkChangeTime;
 };
 
 #endif /* NSNETWORKLINKSERVICE_LINUX_H_ */

netwerk/system/mac/nsNetworkLinkService.h

@@ -8,6 +8,7 @@
 #include "nsINetworkLinkService.h"
 #include "nsIObserver.h"
 #include "mozilla/Mutex.h"
+#include "mozilla/TimeStamp.h"
 
 #include <SystemConfiguration/SCNetworkReachability.h>
 #include <SystemConfiguration/SystemConfiguration.h>
@@ -46,6 +47,9 @@ class nsNetworkLinkService : public nsINetworkLinkService, public nsIObserver {
 
   mozilla::Mutex mMutex;
   nsCString mNetworkId;
+
+  // Time stamp of last NS_NETWORK_LINK_DATA_CHANGED event
+  mozilla::TimeStamp mNetworkChangeTime;
 };
 
 #endif /* NSNETWORKLINKSERVICEMAC_H_ */

netwerk/system/mac/nsNetworkLinkService.mm

@@ -554,6 +554,12 @@ void nsNetworkLinkService::SendEvent(bool aNetworkChanged) {
       return;
     }
     event = NS_NETWORK_LINK_DATA_CHANGED;
+
+    if (!mNetworkChangeTime.IsNull()) {
+      Telemetry::AccumulateTimeDelta(Telemetry::NETWORK_TIME_BETWEEN_NETWORK_CHANGE_EVENTS,
+                                     mNetworkChangeTime);
+    }
+    mNetworkChangeTime = TimeStamp::Now();
   } else if (!mStatusKnown) {
     event = NS_NETWORK_LINK_DATA_UNKNOWN;
   } else {

netwerk/system/win32/nsNotifyAddrListener.cpp

@@ -257,6 +257,13 @@ nsNotifyAddrListener::nextCoalesceWaitTime() {
   // check if coalescing period should continue
   double period = (TimeStamp::Now() - mChangeTime).ToMilliseconds();
   if (period >= kNetworkChangeCoalescingPeriod) {
+    if (!mNetworkChangeTime.IsNull()) {
+      Telemetry::AccumulateTimeDelta(
+          Telemetry::NETWORK_TIME_BETWEEN_NETWORK_CHANGE_EVENTS,
+          mNetworkChangeTime);
+    }
+    mNetworkChangeTime = TimeStamp::Now();
+
     SendEvent(NS_NETWORK_LINK_DATA_CHANGED);
     mCoalescingActive = false;
     return INFINITE;  // return default

netwerk/system/win32/nsNotifyAddrListener.h

@@ -93,6 +93,9 @@ class nsNotifyAddrListener : public nsINetworkLinkService,
 
   // Time stamp for first event during coalescing
   mozilla::TimeStamp mChangeTime;
+
+  // Time stamp of last NS_NETWORK_LINK_DATA_CHANGED event
+  mozilla::TimeStamp mNetworkChangeTime;
 };
 
 #endif /* NSNOTIFYADDRLISTENER_H_ */

toolkit/components/telemetry/Histograms.json

@@ -5378,6 +5378,18 @@
     "n_values": 6,
     "description": "Network identification (0=None, 1=New Ipv4, 2=Same, 3=New IPv6, 4=New dual)"
   },
+  "NETWORK_TIME_BETWEEN_NETWORK_CHANGE_EVENTS": {
+    "record_in_processes": ["main"],
+    "products": ["firefox", "fennec", "geckoview"],
+    "alert_emails": ["necko@mozilla.com", "mnovotny@mozilla.com"],
+    "bug_numbers": [1570932],
+    "expires_in_version": "76",
+    "kind": "exponential",
+    "low": 1000,
+    "high": 600000,
+    "n_buckets": 50,
+    "description": "Time in ms between two NS_NETWORK_LINK_DATA_CHANGED events sent"
+  },
   "IDLE_NOTIFY_IDLE_MS": {
     "record_in_processes": ["main", "content"],
     "products": ["firefox", "fennec", "geckoview"],