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Python

# Copyright (c) 2018 gevent. See LICENSE for details.
# cython: auto_pickle=False,embedsignature=True,always_allow_keywords=False
from __future__ import print_function, absolute_import, division
import sys
import traceback
from greenlet import settrace
from greenlet import getcurrent
from gevent.util import format_run_info
from gevent._compat import perf_counter
from gevent._util import gmctime
__all__ = [
'GreenletTracer',
'HubSwitchTracer',
'MaxSwitchTracer',
]
# Recall these classes are cython compiled, so
# class variable declarations are bad.
class GreenletTracer(object):
def __init__(self):
# A counter, incremented by the greenlet trace function
# we install on every greenlet switch. This is reset when the
# periodic monitoring thread runs.
self.greenlet_switch_counter = 0
# The greenlet last switched to.
self.active_greenlet = None
# The trace function that was previously installed,
# if any.
# NOTE: Calling a class instance is cheaper than
# calling a bound method (at least when compiled with cython)
# even when it redirects to another function.
prev_trace = settrace(self)
self.previous_trace_function = prev_trace
self._killed = False
def kill(self):
# Must be called in the monitored thread.
if not self._killed:
self._killed = True
settrace(self.previous_trace_function)
self.previous_trace_function = None
def _trace(self, event, args):
# This function runs in the thread we are monitoring.
self.greenlet_switch_counter += 1
if event in ('switch', 'throw'):
# args is (origin, target). This is the only defined
# case
self.active_greenlet = args[1]
else:
self.active_greenlet = None
if self.previous_trace_function is not None:
self.previous_trace_function(event, args)
def __call__(self, event, args):
return self._trace(event, args)
def did_block_hub(self, hub):
# Check to see if we have blocked since the last call to this
# method. Returns a true value if we blocked (not in the hub),
# a false value if everything is fine.
# This may be called in the same thread being traced or a
# different thread; if a different thread, there is a race
# condition with this being incremented in the thread we're
# monitoring, but probably not often enough to lead to
# annoying false positives.
active_greenlet = self.active_greenlet
did_switch = self.greenlet_switch_counter != 0
self.greenlet_switch_counter = 0
if did_switch or active_greenlet is None or active_greenlet is hub:
# Either we switched, or nothing is running (we got a
# trace event we don't know about or were requested to
# ignore), or we spent the whole time in the hub, blocked
# for IO. Nothing to report.
return False
return True, active_greenlet
def ignore_current_greenlet_blocking(self):
# Don't pay attention to the current greenlet.
self.active_greenlet = None
def monitor_current_greenlet_blocking(self):
self.active_greenlet = getcurrent()
def did_block_hub_report(self, hub, active_greenlet, format_kwargs):
report = ['=' * 80,
'\n%s : Greenlet %s appears to be blocked' %
(gmctime(), active_greenlet)]
report.append(" Reported by %s" % (self,))
try:
frame = sys._current_frames()[hub.thread_ident]
except KeyError:
# The thread holding the hub has died. Perhaps we shouldn't
# even report this?
stack = ["Unknown: No thread found for hub %r\n" % (hub,)]
else:
stack = traceback.format_stack(frame)
report.append('Blocked Stack (for thread id %s):' % (hex(hub.thread_ident),))
report.append(''.join(stack))
report.append("Info:")
report.extend(format_run_info(**format_kwargs))
return report
class _HubTracer(GreenletTracer):
def __init__(self, hub, max_blocking_time):
GreenletTracer.__init__(self)
self.max_blocking_time = max_blocking_time
self.hub = hub
def kill(self):
self.hub = None
GreenletTracer.kill(self)
class HubSwitchTracer(_HubTracer):
# A greenlet tracer that records the last time we switched *into* the hub.
def __init__(self, hub, max_blocking_time):
_HubTracer.__init__(self, hub, max_blocking_time)
self.last_entered_hub = 0
def _trace(self, event, args):
GreenletTracer._trace(self, event, args)
if self.active_greenlet is self.hub:
self.last_entered_hub = perf_counter()
def did_block_hub(self, hub):
if perf_counter() - self.last_entered_hub > self.max_blocking_time:
return True, self.active_greenlet
class MaxSwitchTracer(_HubTracer):
# A greenlet tracer that records the maximum time between switches,
# not including time spent in the hub.
def __init__(self, hub, max_blocking_time):
_HubTracer.__init__(self, hub, max_blocking_time)
self.last_switch = perf_counter()
self.max_blocking = 0
def _trace(self, event, args):
old_active = self.active_greenlet
GreenletTracer._trace(self, event, args)
if old_active is not self.hub and old_active is not None:
# If we're switching out of the hub, the blocking
# time doesn't count.
switched_at = perf_counter()
self.max_blocking = max(self.max_blocking,
switched_at - self.last_switch)
def did_block_hub(self, hub):
if self.max_blocking == 0:
# We never switched. Check the time now
self.max_blocking = perf_counter() - self.last_switch
if self.max_blocking > self.max_blocking_time:
return True, self.active_greenlet
from gevent._util import import_c_accel
import_c_accel(globals(), 'gevent.__tracer')