From e4bf7066f3e1c78de7dfacbe727ba4c277e51cd9 Mon Sep 17 00:00:00 2001
From: Anders Kaseorg <anders@zulip.com>
Date: Thu, 17 Mar 2022 14:13:37 -0700
Subject: [PATCH] tornado: Remove instrument_tornado_ioloop.

Signed-off-by: Anders Kaseorg <anders@zulip.com>
---
 zerver/management/commands/runtornado.py |  8 ---
 zerver/tornado/ioloop_logging.py         | 80 +-----------------------
 2 files changed, 1 insertion(+), 87 deletions(-)

diff --git a/zerver/management/commands/runtornado.py b/zerver/management/commands/runtornado.py
index 935efe778e..0db0a30888 100644
--- a/zerver/management/commands/runtornado.py
+++ b/zerver/management/commands/runtornado.py
@@ -9,15 +9,7 @@ from django.core.management.base import BaseCommand, CommandError, CommandParser
 from tornado import autoreload, ioloop
 from tornado.log import app_log
 
-# We must call zerver.tornado.ioloop_logging.instrument_tornado_ioloop
-# before we import anything else from our project in order for our
-# Tornado load logging to work; otherwise we might accidentally import
-# zerver.lib.queue (which will instantiate the Tornado ioloop) before
-# this.
-from zerver.tornado.ioloop_logging import instrument_tornado_ioloop
-
 settings.RUNNING_INSIDE_TORNADO = True
-instrument_tornado_ioloop()
 
 from zerver.lib.debug import interactive_debug_listen
 from zerver.tornado.application import create_tornado_application, setup_tornado_rabbitmq
diff --git a/zerver/tornado/ioloop_logging.py b/zerver/tornado/ioloop_logging.py
index 86a3a50c27..de6ac93cd8 100644
--- a/zerver/tornado/ioloop_logging.py
+++ b/zerver/tornado/ioloop_logging.py
@@ -1,83 +1,5 @@
-import logging
-import select
-import time
-from typing import Any, Dict, List, Tuple
-
-from django.conf import settings
-from tornado.ioloop import IOLoop, PollIOLoop
-
-# There isn't a good way to get at what the underlying poll implementation
-# will be without actually constructing an IOLoop, so we just assume it will
-# be epoll.
-orig_poll_impl = select.epoll
+from typing import Dict
 
 # This is used for a somewhat hacky way of passing the port number
 # into this early-initialized module.
 logging_data: Dict[str, str] = {}
-
-
-class InstrumentedPollIOLoop(PollIOLoop):
-    def initialize(self, **kwargs):  # type: ignore[no-untyped-def] # TODO investigate likely buggy monkey patching here
-        super().initialize(impl=InstrumentedPoll(), **kwargs)
-
-
-def instrument_tornado_ioloop() -> None:
-    IOLoop.configure(InstrumentedPollIOLoop)
-
-
-# A hack to keep track of how much time we spend working, versus sleeping in
-# the event loop.
-#
-# Creating a new event loop instance with a custom impl object fails (events
-# don't get processed), so instead we modify the ioloop module variable holding
-# the default poll implementation.  We need to do this before any Tornado code
-# runs that might instantiate the default event loop.
-
-
-class InstrumentedPoll:
-    def __init__(self) -> None:
-        self._underlying = orig_poll_impl()
-        self._times: List[Tuple[float, float]] = []
-        self._last_print = 0.0
-
-    # Python won't let us subclass e.g. select.epoll, so instead
-    # we proxy every method.  __getattr__ handles anything we
-    # don't define elsewhere.
-    def __getattr__(self, name: str) -> Any:
-        return getattr(self._underlying, name)
-
-    # Call the underlying poll method, and report timing data.
-    def poll(self, timeout: float) -> Any:
-
-        # Avoid accumulating a bunch of insignificant data points
-        # from short timeouts.
-        if timeout < 1e-3:
-            return self._underlying.poll(timeout)
-
-        # Record start and end times for the underlying poll
-        t0 = time.time()
-        result = self._underlying.poll(timeout)
-        t1 = time.time()
-
-        # Log this data point and restrict our log to the past minute
-        self._times.append((t0, t1))
-        while self._times and self._times[0][0] < t1 - 60:
-            self._times.pop(0)
-
-        # Report (at most once every 5s) the percentage of time spent
-        # outside poll
-        if self._times and t1 - self._last_print >= 5:
-            total = t1 - self._times[0][0]
-            in_poll = sum(b - a for a, b in self._times)
-            if total > 0:
-                percent_busy = 100 * (1 - in_poll / total)
-                if settings.PRODUCTION:
-                    logging.info(
-                        "Tornado %s %5.1f%% busy over the past %4.1f seconds",
-                        logging_data.get("port", "unknown"),
-                        percent_busy,
-                        total,
-                    )
-                    self._last_print = t1
-
-        return result