greenlet_trace.py

import gevent
import greenlet
import logging
import time
import traceback

_last_switch_time = None
_min_elapsed_time = 0.1

def trace(event, (origin, target)):
    global _last_switch_time
    last_switch_time = _last_switch_time
    current_time = _last_switch_time = time.time()
    if last_switch_time is not None:
        elapsed_time = current_time - last_switch_time
        if elapsed_time < _min_elapsed_time:
            return
        if origin is gevent.hub.get_hub():
            return
        logging.error('greenlet blocked event loop for %.4f seconds: %s',
                      elapsed_time, traceback.format_stack())

greenlet.settrace(trace)