v8/tools/testrunner/local/pool.py
machenbach a54f22d418 Make test runner more chatty to avoid it getting killed by buildbot.
NOTRY=true
NOTREECHECKS=true

Review URL: https://codereview.chromium.org/1064043002

Cr-Commit-Position: refs/heads/master@{#27653}
2015-04-08 09:53:39 +00:00

173 lines
5.2 KiB
Python

#!/usr/bin/env python
# Copyright 2014 the V8 project authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
from Queue import Empty
from multiprocessing import Event, Process, Queue
class NormalResult():
def __init__(self, result):
self.result = result
self.exception = False
self.break_now = False
class ExceptionResult():
def __init__(self):
self.exception = True
self.break_now = False
class BreakResult():
def __init__(self):
self.exception = False
self.break_now = True
class MaybeResult():
def __init__(self, heartbeat, value):
self.heartbeat = heartbeat
self.value = value
@staticmethod
def create_heartbeat():
return MaybeResult(True, None)
@staticmethod
def create_result(value):
return MaybeResult(False, value)
def Worker(fn, work_queue, done_queue, done):
"""Worker to be run in a child process.
The worker stops on two conditions. 1. When the poison pill "STOP" is
reached or 2. when the event "done" is set."""
try:
for args in iter(work_queue.get, "STOP"):
if done.is_set():
break
try:
done_queue.put(NormalResult(fn(*args)))
except Exception, e:
print(">>> EXCEPTION: %s" % e)
done_queue.put(ExceptionResult())
except KeyboardInterrupt:
done_queue.put(BreakResult())
class Pool():
"""Distributes tasks to a number of worker processes.
New tasks can be added dynamically even after the workers have been started.
Requirement: Tasks can only be added from the parent process, e.g. while
consuming the results generator."""
# Factor to calculate the maximum number of items in the work/done queue.
# Necessary to not overflow the queue's pipe if a keyboard interrupt happens.
BUFFER_FACTOR = 4
def __init__(self, num_workers, heartbeat_timeout=30):
self.num_workers = num_workers
self.processes = []
self.terminated = False
# Invariant: count >= #work_queue + #done_queue. It is greater when a
# worker takes an item from the work_queue and before the result is
# submitted to the done_queue. It is equal when no worker is working,
# e.g. when all workers have finished, and when no results are processed.
# Count is only accessed by the parent process. Only the parent process is
# allowed to remove items from the done_queue and to add items to the
# work_queue.
self.count = 0
self.work_queue = Queue()
self.done_queue = Queue()
self.done = Event()
self.heartbeat_timeout = heartbeat_timeout
def imap_unordered(self, fn, gen):
"""Maps function "fn" to items in generator "gen" on the worker processes
in an arbitrary order. The items are expected to be lists of arguments to
the function. Returns a results iterator. A result value of type
MaybeResult either indicates a heartbeat of the runner, i.e. indicating
that the runner is still waiting for the result to be computed, or it wraps
the real result."""
try:
gen = iter(gen)
self.advance = self._advance_more
for w in xrange(self.num_workers):
p = Process(target=Worker, args=(fn,
self.work_queue,
self.done_queue,
self.done))
self.processes.append(p)
p.start()
self.advance(gen)
while self.count > 0:
while True:
try:
result = self.done_queue.get(timeout=self.heartbeat_timeout)
break
except Empty:
# Indicate a heartbeat. The iterator will continue fetching the
# next result.
yield MaybeResult.create_heartbeat()
self.count -= 1
if result.exception:
# Ignore items with unexpected exceptions.
continue
elif result.break_now:
# A keyboard interrupt happened in one of the worker processes.
raise KeyboardInterrupt
else:
yield MaybeResult.create_result(result.result)
self.advance(gen)
finally:
self.terminate()
def _advance_more(self, gen):
while self.count < self.num_workers * self.BUFFER_FACTOR:
try:
self.work_queue.put(gen.next())
self.count += 1
except StopIteration:
self.advance = self._advance_empty
break
def _advance_empty(self, gen):
pass
def add(self, args):
"""Adds an item to the work queue. Can be called dynamically while
processing the results from imap_unordered."""
self.work_queue.put(args)
self.count += 1
def terminate(self):
if self.terminated:
return
self.terminated = True
# For exceptional tear down set the "done" event to stop the workers before
# they empty the queue buffer.
self.done.set()
for p in self.processes:
# During normal tear down the workers block on get(). Feed a poison pill
# per worker to make them stop.
self.work_queue.put("STOP")
for p in self.processes:
p.join()
# Drain the queues to prevent failures when queues are garbage collected.
try:
while True: self.work_queue.get(False)
except:
pass
try:
while True: self.done_queue.get(False)
except:
pass