mirror of https://github.com/zulip/zulip.git
72 lines
2.6 KiB
Python
72 lines
2.6 KiB
Python
import logging
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import select
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import time
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from typing import Any, List, Tuple
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from django.conf import settings
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from tornado.ioloop import IOLoop, PollIOLoop
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# There isn't a good way to get at what the underlying poll implementation
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# will be without actually constructing an IOLoop, so we just assume it will
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# be epoll.
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orig_poll_impl = select.epoll
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class InstrumentedPollIOLoop(PollIOLoop):
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def initialize(self, **kwargs): # type: ignore # TODO investigate likely buggy monkey patching here
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super().initialize(impl=InstrumentedPoll(), **kwargs)
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def instrument_tornado_ioloop() -> None:
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IOLoop.configure(InstrumentedPollIOLoop)
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# A hack to keep track of how much time we spend working, versus sleeping in
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# the event loop.
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#
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# Creating a new event loop instance with a custom impl object fails (events
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# don't get processed), so instead we modify the ioloop module variable holding
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# the default poll implementation. We need to do this before any Tornado code
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# runs that might instantiate the default event loop.
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class InstrumentedPoll:
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def __init__(self) -> None:
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self._underlying = orig_poll_impl()
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self._times = [] # type: List[Tuple[float, float]]
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self._last_print = 0.0
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# Python won't let us subclass e.g. select.epoll, so instead
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# we proxy every method. __getattr__ handles anything we
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# don't define elsewhere.
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def __getattr__(self, name: str) -> Any:
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return getattr(self._underlying, name)
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# Call the underlying poll method, and report timing data.
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def poll(self, timeout: float) -> Any:
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# Avoid accumulating a bunch of insignificant data points
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# from short timeouts.
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if timeout < 1e-3:
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return self._underlying.poll(timeout)
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# Record start and end times for the underlying poll
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t0 = time.time()
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result = self._underlying.poll(timeout)
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t1 = time.time()
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# Log this datapoint and restrict our log to the past minute
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self._times.append((t0, t1))
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while self._times and self._times[0][0] < t1 - 60:
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self._times.pop(0)
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# Report (at most once every 5s) the percentage of time spent
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# outside poll
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if self._times and t1 - self._last_print >= 5:
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total = t1 - self._times[0][0]
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in_poll = sum(b-a for a, b in self._times)
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if total > 0:
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percent_busy = 100 * (1 - in_poll / total)
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if settings.PRODUCTION:
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logging.info('Tornado %5.1f%% busy over the past %4.1f seconds'
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% (percent_busy, total))
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self._last_print = t1
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return result
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