Bump default GC threshold to 1GB

In our testing we observe no meaningfully different peak
memory (carrier size) limit and 18 to 65% lower tail latencies
with small messages, and teen % lower with 50 MB messages.

Throughput is single digit % higher.

CPU usage was not meaningfully different on a four core host.

References rabbitmq/rabbitmq-common#343.

1 files changed, 2 insertions, 2 deletions

diff --git a/Makefile b/Makefile
index 9a8a936c69..fa1ec6519f 100644
--- a/Makefile
+++ b/Makefile
@@ -130,8 +130,8 @@ define PROJECT_ENV
 	    {channel_tick_interval, 60000},
 	    %% Default max message size is 128 MB
 	    {max_message_size, 134217728},
-	    %% Default is ~ 1MB
-	    {gc_threshold, 1000000}
+	    %% Socket writer will run GC every 1 GB of outgoing data
+	    {gc_threshold, 1000000000}
 	  ]
 endef