[PR #8662/be23d16f backport][3.10] Improve performance of keepalive r…

…escheduling (#8670)

Co-authored-by: J. Nick Koston <nick@koston.org>

CHANGES/8662.misc.rst

@@ -0,0 +1,3 @@
+Improved performance of HTTP keep-alive checks -- by :user:`bdraco`.
+
+Previously, when processing a request for a keep-alive connection, the keep-alive check would happen every second; the check is now rescheduled if it fires too early instead.

aiohttp/web_protocol.py

@@ -134,16 +134,14 @@ class RequestHandler(BaseProtocol):
 
     """
 
-    KEEPALIVE_RESCHEDULE_DELAY = 1
-
     __slots__ = (
         "_request_count",
         "_keepalive",
         "_manager",
         "_request_handler",
         "_request_factory",
         "_tcp_keepalive",
-        "_keepalive_time",
+        "_next_keepalive_close_time",
         "_keepalive_handle",
         "_keepalive_timeout",
         "_lingering_time",
@@ -197,7 +195,7 @@ def __init__(
 
         self._tcp_keepalive = tcp_keepalive
         # placeholder to be replaced on keepalive timeout setup
-        self._keepalive_time = 0.0
+        self._next_keepalive_close_time = 0.0
         self._keepalive_handle: Optional[asyncio.Handle] = None
         self._keepalive_timeout = keepalive_timeout
         self._lingering_time = float(lingering_time)
@@ -429,23 +427,21 @@ def log_exception(self, *args: Any, **kw: Any) -> None:
         self.logger.exception(*args, **kw)
 
     def _process_keepalive(self) -> None:
+        self._keepalive_handle = None
         if self._force_close or not self._keepalive:
             return
 
-        next = self._keepalive_time + self._keepalive_timeout
+        loop = self._loop
+        now = loop.time()
+        close_time = self._next_keepalive_close_time
+        if now <= close_time:
+            # Keep alive close check fired too early, reschedule
+            self._keepalive_handle = loop.call_at(close_time, self._process_keepalive)
+            return
 
         # handler in idle state
         if self._waiter:
-            if self._loop.time() > next:
-                self.force_close()
-                return
-
-        # not all request handlers are done,
-        # reschedule itself to next second
-        self._keepalive_handle = self._loop.call_later(
-            self.KEEPALIVE_RESCHEDULE_DELAY,
-            self._process_keepalive,
-        )
+            self.force_close()
 
     async def _handle_request(
         self,
@@ -596,11 +592,12 @@ async def start(self) -> None:
                     if self._keepalive and not self._close:
                         # start keep-alive timer
                         if keepalive_timeout is not None:
-                            now = self._loop.time()
-                            self._keepalive_time = now
+                            now = loop.time()
+                            close_time = now + keepalive_timeout
+                            self._next_keepalive_close_time = close_time
                             if self._keepalive_handle is None:
                                 self._keepalive_handle = loop.call_at(
-                                    now + keepalive_timeout, self._process_keepalive
+                                    close_time, self._process_keepalive
                                 )
                     else:
                         break