Record and report on time spent in listen_disabled

4 files changed, 16 insertions, 4 deletions

diff --git a/memcached.c b/memcached.c
index d3c2a63..47d7430 100644
--- a/memcached.c
+++ b/memcached.c
@@ -185,6 +185,7 @@ static void stats_init(void) {
     stats.slab_reassign_running = false;
     stats.lru_crawler_running = false;
     stats.lru_crawler_starts = 0;
+    stats.time_in_listen_disabled_us = 0;
 
     /* make the time we started always be 2 seconds before we really
        did, so time(0) - time.started is never zero.  if so, things
@@ -2623,6 +2624,7 @@ static void server_stats(ADD_STAT add_stats, conn *c) {
     APPEND_STAT("limit_maxbytes", "%llu", (unsigned long long)settings.maxbytes);
     APPEND_STAT("accepting_conns", "%u", stats.accepting_conns);
     APPEND_STAT("listen_disabled_num", "%llu", (unsigned long long)stats.listen_disabled_num);
+    APPEND_STAT("time_in_listen_disabled_us", "%llu", stats.time_in_listen_disabled_us);
     APPEND_STAT("threads", "%d", settings.num_threads);
     APPEND_STAT("conn_yields", "%llu", (unsigned long long)thread_stats.conn_yields);
     APPEND_STAT("hash_power_level", "%u", stats.hash_power_level);
@@ -3953,11 +3955,19 @@ void do_accept_new_conns(const bool do_accept) {
 
     if (do_accept) {
         STATS_LOCK();
+        struct timeval maxconns_exited;
+        uint64_t elapsed_us;
+        gettimeofday(&maxconns_exited,NULL);
+        elapsed_us =
+            (maxconns_exited.tv_sec - stats.maxconns_entered.tv_sec) * 1000000
+            + (maxconns_exited.tv_usec - stats.maxconns_entered.tv_usec);
+        stats.time_in_listen_disabled_us += elapsed_us;
         stats.accepting_conns = true;
         STATS_UNLOCK();
     } else {
         STATS_LOCK();
         stats.accepting_conns = false;
+        gettimeofday(&stats.maxconns_entered,NULL);
         stats.listen_disabled_num++;
         STATS_UNLOCK();
         allow_new_conns = false;
diff --git a/memcached.h b/memcached.h
index 99cf0b5..4ae3164 100644
--- a/memcached.h
+++ b/memcached.h
@@ -288,6 +288,8 @@ struct stats {
     uint64_t      lru_crawler_starts; /* Number of item crawlers kicked off */
     bool          lru_crawler_running; /* crawl in progress */
     uint64_t      lru_maintainer_juggles; /* number of LRU bg pokes */
+    uint64_t      time_in_listen_disabled_us;  /* elapsed time in microseconds while server unable to process new connections */
+    struct timeval maxconns_entered;  /* last time maxconns entered */
 };
 
 #define MAX_VERBOSITY_LEVEL 2
diff --git a/t/binary.t b/t/binary.t
index 3ee0823..ae28814 100755
--- a/t/binary.t
+++ b/t/binary.t
@@ -61,7 +61,6 @@ my $mc = MC::Client->new;
 # Let's turn on detail stats for all this stuff
 
 $mc->stats('detail on');
-
 my $check = sub {
     my ($key, $orig_flags, $orig_val) = @_;
     my ($flags, $val, $cas) = $mc->get($key);
diff --git a/t/stats.t b/t/stats.t
index 92f96f0..81f780f 100755
--- a/t/stats.t
+++ b/t/stats.t
@@ -1,7 +1,7 @@
 #!/usr/bin/perl
 
 use strict;
-use Test::More tests => 97;
+use Test::More tests => 98;
 use FindBin qw($Bin);
 use lib "$Bin/lib";
 use MemcachedTest;
@@ -48,6 +48,7 @@ my $sock = $server->sock;
 ## STAT limit_maxbytes 67108864
 ## STAT accepting_conns 1
 ## STAT listen_disabled_num 0
+## STAT time_in_listen_disabled_us 0
 ## STAT threads 4
 ## STAT conn_yields 0
 ## STAT hash_power_level 16
@@ -70,12 +71,12 @@ my $sock = $server->sock;
 my $stats = mem_stats($sock);
 
 # Test number of keys
-is(scalar(keys(%$stats)), 52, "52 stats values");
+is(scalar(keys(%$stats)), 52, "53 stats values");
 
 # Test initial state
 foreach my $key (qw(curr_items total_items bytes cmd_get cmd_set get_hits evictions get_misses
                  bytes_written delete_hits delete_misses incr_hits incr_misses decr_hits
-                 decr_misses listen_disabled_num lrutail_reflocked)) {
+                 decr_misses listen_disabled_num lrutail_reflocked time_in_listen_disabled_us)) {
     is($stats->{$key}, 0, "initial $key is zero");
 }
 is($stats->{accepting_conns}, 1, "initial accepting_conns is one");