add stat to measure additional config age

Summary: If we call two reconfiguration callbacks for two config sources, we need to measure the ages for both.

Reviewed By: stuclar

Differential Revision: D64807435

fbshipit-source-id: b0c1f777fb2a193451d4d1bf1fe21e81e0982187

mcrouter/stat_list.h

@@ -363,8 +363,10 @@ STAT(retrans_per_kbyte_avg, stat_double, 0, .dbl = 0.0)
  */
 #define GROUP ods_stats | detailed_stats
 STUI(config_age, 0, 0)
+STUI(config_age_sr, 0, 0)
 STUI(config_last_attempt, 0, 0)
 STUI(config_last_success, 0, 0)
+STUI(config_last_sr_update, 0, 0)
 STUI(config_failures, 0, 0)
 STUI(configs_from_disk, 0, 0)
 STUI(config_partial_reconfig_attempt, 0, 0)

mcrouter/stats.cpp

@@ -379,6 +379,7 @@ void prepare_stats(CarbonRouterInstanceBase& router, stat_t* stats) {
   init_stats(stats);
 
   uint64_t config_last_success = 0;
+  uint64_t config_last_sr_update = 0;
   uint64_t destinationBatchesSum = 0;
   uint64_t destinationRequestsSum = 0;
   uint64_t outstandingGetReqsTotal = 0;
@@ -396,6 +397,10 @@ void prepare_stats(CarbonRouterInstanceBase& router, stat_t* stats) {
     auto proxy = router.getProxyBase(i);
     config_last_success = std::max(
         config_last_success, proxy->stats().getValue(config_last_success_stat));
+    config_last_sr_update = std::max(
+        config_last_sr_update,
+        proxy->stats().getValue(config_last_sr_update_stat));
+
     destinationBatchesSum +=
         proxy->stats().getStatValueWithinWindow(destination_batches_sum_stat);
     destinationRequestsSum +=
@@ -486,6 +491,8 @@ void prepare_stats(CarbonRouterInstanceBase& router, stat_t* stats) {
   stat_set(stats, time_stat, now);
   stat_set(stats, uptime_stat, now - router.startTime());
   stat_set(stats, config_age_stat, now - config_last_success);
+  stat_set(stats, config_age_sr_stat, now - config_last_sr_update);
+  stat_set(stats, config_last_sr_update_stat, config_last_sr_update);
   stat_set(stats, config_last_success_stat, config_last_success);
   stat_set(
       stats,