Puma keepalive patch

keepalive.patch

From df72887170c7ef3614c941c9bdefb4a1f3546ebf Mon Sep 17 00:00:00 2001
From: Nate Berkopec <[email protected]>
Date: Tue, 11 May 2021 07:43:32 -0600
Subject: [PATCH] Close keepalive connections after MAX_FAST_INLINE requests

---
 lib/puma/server.rb | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/lib/puma/server.rb b/lib/puma/server.rb
index 3912699c..32bdbd2e 100644
--- a/lib/puma/server.rb
+++ b/lib/puma/server.rb
@@ -447,15 +447,20 @@ module Puma
 
             requests += 1
 
-            check_for_more_data = @status == :run
+            # Closing keepalive sockets after they've made a reasonable
+            # number of requests allows Puma to service many connections
+            # fairly, even when the number of concurrent connections exceeds
+            # the size of the threadpool. It also allows cluster mode Pumas
+            # to keep load evenly distributed across workers, because clients
+            # are randomly assigned a new worker when opening a new connection.
+            #
+            # Previously, Puma would kick connections in this conditional back
+            # to the reactor. However, because this causes the todo set to increase
+            # in size, the wait_until_full mutex would never unlock, leaving
+            # any additional connections unserviced.
+            break if requests >= @max_fast_inline
 
-            if requests >= @max_fast_inline
-              # This will mean that reset will only try to use the data it already
-              # has buffered and won't try to read more data. What this means is that
-              # every client, independent of their request speed, gets treated like a slow
-              # one once every max_fast_inline requests.
-              check_for_more_data = false
-            end
+            check_for_more_data = @status == :run
 
             next_request_ready = with_force_shutdown(client) do
               client.reset(check_for_more_data)
-- 
2.30.1 (Apple Git-130)

patch

patch