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Diffstat (limited to 'python/gevent/_tracer.py')
| -rw-r--r-- | python/gevent/_tracer.py | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/python/gevent/_tracer.py b/python/gevent/_tracer.py new file mode 100644 index 0000000..98307ab --- /dev/null +++ b/python/gevent/_tracer.py @@ -0,0 +1,179 @@ +# 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') |