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30913031d4
The home of 'Abort' is 'error' not 'util' however, a lot of code seems to be confused about that and gives all the credit to 'util' instead of the hardworking 'error'. In a spirit of equity, we break the cycle of injustice and give back to 'error' the respect it deserves. And screw that 'util' poser. For great justice.
166 lines
4.4 KiB
Python
166 lines
4.4 KiB
Python
# worker.py - master-slave parallelism support
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#
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# Copyright 2013 Facebook, Inc.
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#
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# This software may be used and distributed according to the terms of the
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# GNU General Public License version 2 or any later version.
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from __future__ import absolute_import
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import errno
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import os
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import signal
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import sys
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import threading
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from .i18n import _
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from . import error
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def countcpus():
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'''try to count the number of CPUs on the system'''
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# posix
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try:
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n = int(os.sysconf('SC_NPROCESSORS_ONLN'))
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if n > 0:
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return n
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except (AttributeError, ValueError):
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pass
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# windows
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try:
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n = int(os.environ['NUMBER_OF_PROCESSORS'])
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if n > 0:
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return n
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except (KeyError, ValueError):
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pass
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return 1
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def _numworkers(ui):
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s = ui.config('worker', 'numcpus')
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if s:
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try:
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n = int(s)
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if n >= 1:
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return n
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except ValueError:
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raise error.Abort(_('number of cpus must be an integer'))
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return min(max(countcpus(), 4), 32)
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if os.name == 'posix':
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_startupcost = 0.01
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else:
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_startupcost = 1e30
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def worthwhile(ui, costperop, nops):
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'''try to determine whether the benefit of multiple processes can
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outweigh the cost of starting them'''
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linear = costperop * nops
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workers = _numworkers(ui)
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benefit = linear - (_startupcost * workers + linear / workers)
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return benefit >= 0.15
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def worker(ui, costperarg, func, staticargs, args):
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'''run a function, possibly in parallel in multiple worker
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processes.
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returns a progress iterator
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costperarg - cost of a single task
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func - function to run
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staticargs - arguments to pass to every invocation of the function
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args - arguments to split into chunks, to pass to individual
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workers
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'''
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if worthwhile(ui, costperarg, len(args)):
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return _platformworker(ui, func, staticargs, args)
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return func(*staticargs + (args,))
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def _posixworker(ui, func, staticargs, args):
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rfd, wfd = os.pipe()
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workers = _numworkers(ui)
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oldhandler = signal.getsignal(signal.SIGINT)
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signal.signal(signal.SIGINT, signal.SIG_IGN)
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pids, problem = [], [0]
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for pargs in partition(args, workers):
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pid = os.fork()
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if pid == 0:
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signal.signal(signal.SIGINT, oldhandler)
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try:
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os.close(rfd)
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for i, item in func(*(staticargs + (pargs,))):
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os.write(wfd, '%d %s\n' % (i, item))
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os._exit(0)
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except KeyboardInterrupt:
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os._exit(255)
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# other exceptions are allowed to propagate, we rely
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# on lock.py's pid checks to avoid release callbacks
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pids.append(pid)
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pids.reverse()
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os.close(wfd)
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fp = os.fdopen(rfd, 'rb', 0)
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def killworkers():
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# if one worker bails, there's no good reason to wait for the rest
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for p in pids:
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try:
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os.kill(p, signal.SIGTERM)
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except OSError as err:
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if err.errno != errno.ESRCH:
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raise
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def waitforworkers():
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for _pid in pids:
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st = _exitstatus(os.wait()[1])
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if st and not problem[0]:
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problem[0] = st
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killworkers()
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t = threading.Thread(target=waitforworkers)
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t.start()
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def cleanup():
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signal.signal(signal.SIGINT, oldhandler)
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t.join()
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status = problem[0]
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if status:
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if status < 0:
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os.kill(os.getpid(), -status)
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sys.exit(status)
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try:
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for line in fp:
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l = line.split(' ', 1)
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yield int(l[0]), l[1][:-1]
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except: # re-raises
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killworkers()
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cleanup()
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raise
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cleanup()
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def _posixexitstatus(code):
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'''convert a posix exit status into the same form returned by
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os.spawnv
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returns None if the process was stopped instead of exiting'''
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if os.WIFEXITED(code):
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return os.WEXITSTATUS(code)
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elif os.WIFSIGNALED(code):
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return -os.WTERMSIG(code)
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if os.name != 'nt':
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_platformworker = _posixworker
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_exitstatus = _posixexitstatus
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def partition(lst, nslices):
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'''partition a list into N slices of equal size'''
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n = len(lst)
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chunk, slop = n / nslices, n % nslices
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end = 0
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for i in xrange(nslices):
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start = end
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end = start + chunk
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if slop:
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end += 1
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slop -= 1
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yield lst[start:end]
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