mercurial/worker.py
author Pierre-Yves David <pierre-yves.david@ens-lyon.org>
Thu, 03 Nov 2016 05:10:14 +0100
changeset 30280 0269ab4f4371
parent 28292 3eb7faf6d958
child 30396 78a58dcf8853
permissions -rw-r--r--
tests: merge 'test-push-validation.t' into 'test-push.t' That test file is very small and is merge with the new 'test-push.t'. No logic is changed but repository name are update to avoid collision. We don't register this as a copy because is actually a "ypoc" merging two file together without replacing the destination and Mercurial cannot express that.
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
18635
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     1
# worker.py - master-slave parallelism support
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     2
#
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     3
# Copyright 2013 Facebook, Inc.
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     4
#
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     5
# This software may be used and distributed according to the terms of the
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     6
# GNU General Public License version 2 or any later version.
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
     7
25992
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
     8
from __future__ import absolute_import
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
     9
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    10
import errno
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    11
import os
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    12
import signal
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    13
import sys
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    14
import threading
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    15
2d76f8a2d831 worker: use absolute_import
Gregory Szorc <gregory.szorc@gmail.com>
parents: 25660
diff changeset
    16
from .i18n import _
26587
56b2bcea2529 error: get Abort from 'error' instead of 'util'
Pierre-Yves David <pierre-yves.david@fb.com>
parents: 26568
diff changeset
    17
from . import error
18635
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
    18
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
    19
def countcpus():
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
    20
    '''try to count the number of CPUs on the system'''
26568
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    21
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    22
    # posix
18635
fed06dd07665 worker: count the number of CPUs
Bryan O'Sullivan <bryano@fb.com>
parents:
diff changeset
    23
    try:
26568
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    24
        n = int(os.sysconf('SC_NPROCESSORS_ONLN'))
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    25
        if n > 0:
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    26
            return n
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    27
    except (AttributeError, ValueError):
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    28
        pass
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    29
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    30
    # windows
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    31
    try:
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    32
        n = int(os.environ['NUMBER_OF_PROCESSORS'])
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    33
        if n > 0:
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    34
            return n
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    35
    except (KeyError, ValueError):
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    36
        pass
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    37
c0501c26b05c worker: restore old countcpus code (issue4869)
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26063
diff changeset
    38
    return 1
18636
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    39
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    40
def _numworkers(ui):
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    41
    s = ui.config('worker', 'numcpus')
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    42
    if s:
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    43
        try:
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    44
            n = int(s)
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    45
            if n >= 1:
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    46
                return n
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    47
        except ValueError:
26587
56b2bcea2529 error: get Abort from 'error' instead of 'util'
Pierre-Yves David <pierre-yves.david@fb.com>
parents: 26568
diff changeset
    48
            raise error.Abort(_('number of cpus must be an integer'))
18636
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    49
    return min(max(countcpus(), 4), 32)
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    50
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    51
if os.name == 'posix':
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    52
    _startupcost = 0.01
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    53
else:
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    54
    _startupcost = 1e30
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    55
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    56
def worthwhile(ui, costperop, nops):
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    57
    '''try to determine whether the benefit of multiple processes can
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    58
    outweigh the cost of starting them'''
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    59
    linear = costperop * nops
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    60
    workers = _numworkers(ui)
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    61
    benefit = linear - (_startupcost * workers + linear / workers)
dcb27c153a40 worker: estimate whether it's worth running a task in parallel
Bryan O'Sullivan <bryano@fb.com>
parents: 18635
diff changeset
    62
    return benefit >= 0.15
18637
ac4dbceeb14a worker: partition a list (of tasks) into equal-sized chunks
Bryan O'Sullivan <bryano@fb.com>
parents: 18636
diff changeset
    63
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    64
def worker(ui, costperarg, func, staticargs, args):
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    65
    '''run a function, possibly in parallel in multiple worker
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    66
    processes.
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    67
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    68
    returns a progress iterator
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    69
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    70
    costperarg - cost of a single task
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    71
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    72
    func - function to run
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    73
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    74
    staticargs - arguments to pass to every invocation of the function
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    75
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    76
    args - arguments to split into chunks, to pass to individual
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    77
    workers
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    78
    '''
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    79
    if worthwhile(ui, costperarg, len(args)):
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    80
        return _platformworker(ui, func, staticargs, args)
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    81
    return func(*staticargs + (args,))
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    82
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    83
def _posixworker(ui, func, staticargs, args):
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    84
    rfd, wfd = os.pipe()
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    85
    workers = _numworkers(ui)
18708
86524a70c0f6 worker: fix a race in SIGINT handling
Bryan O'Sullivan <bryano@fb.com>
parents: 18707
diff changeset
    86
    oldhandler = signal.getsignal(signal.SIGINT)
86524a70c0f6 worker: fix a race in SIGINT handling
Bryan O'Sullivan <bryano@fb.com>
parents: 18707
diff changeset
    87
    signal.signal(signal.SIGINT, signal.SIG_IGN)
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
    88
    pids, problem = [], [0]
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    89
    for pargs in partition(args, workers):
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    90
        pid = os.fork()
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    91
        if pid == 0:
18708
86524a70c0f6 worker: fix a race in SIGINT handling
Bryan O'Sullivan <bryano@fb.com>
parents: 18707
diff changeset
    92
            signal.signal(signal.SIGINT, oldhandler)
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    93
            try:
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    94
                os.close(rfd)
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    95
                for i, item in func(*(staticargs + (pargs,))):
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    96
                    os.write(wfd, '%d %s\n' % (i, item))
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    97
                os._exit(0)
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    98
            except KeyboardInterrupt:
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
    99
                os._exit(255)
19408
c7ec39c1a381 worker: properly report errors from worker processes (issue3982)
Matt Mackall <mpm@selenic.com>
parents: 19406
diff changeset
   100
                # other exceptions are allowed to propagate, we rely
c7ec39c1a381 worker: properly report errors from worker processes (issue3982)
Matt Mackall <mpm@selenic.com>
parents: 19406
diff changeset
   101
                # on lock.py's pid checks to avoid release callbacks
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   102
        pids.append(pid)
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   103
    pids.reverse()
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   104
    os.close(wfd)
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   105
    fp = os.fdopen(rfd, 'rb', 0)
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   106
    def killworkers():
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   107
        # if one worker bails, there's no good reason to wait for the rest
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   108
        for p in pids:
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   109
            try:
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   110
                os.kill(p, signal.SIGTERM)
25660
328739ea70c3 global: mass rewrite to use modern exception syntax
Gregory Szorc <gregory.szorc@gmail.com>
parents: 22199
diff changeset
   111
            except OSError as err:
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   112
                if err.errno != errno.ESRCH:
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   113
                    raise
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   114
    def waitforworkers():
22199
b3e51675f98e cleanup: avoid _ for local unused tmp variables - that is reserved for i18n
Mads Kiilerich <madski@unity3d.com>
parents: 20034
diff changeset
   115
        for _pid in pids:
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   116
            st = _exitstatus(os.wait()[1])
19406
3185b347ae98 worker: check problem state correctly (issue3982)
Matt Mackall <mpm@selenic.com>
parents: 18914
diff changeset
   117
            if st and not problem[0]:
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   118
                problem[0] = st
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   119
                killworkers()
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   120
    t = threading.Thread(target=waitforworkers)
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   121
    t.start()
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   122
    def cleanup():
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   123
        signal.signal(signal.SIGINT, oldhandler)
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   124
        t.join()
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   125
        status = problem[0]
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   126
        if status:
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   127
            if status < 0:
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   128
                os.kill(os.getpid(), -status)
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   129
            sys.exit(status)
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   130
    try:
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   131
        for line in fp:
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   132
            l = line.split(' ', 1)
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   133
            yield int(l[0]), l[1][:-1]
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   134
    except: # re-raises
18709
9955fc5ee24b worker: handle worker failures more aggressively
Bryan O'Sullivan <bryano@fb.com>
parents: 18708
diff changeset
   135
        killworkers()
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   136
        cleanup()
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   137
        raise
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   138
    cleanup()
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   139
18707
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   140
def _posixexitstatus(code):
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   141
    '''convert a posix exit status into the same form returned by
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   142
    os.spawnv
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   143
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   144
    returns None if the process was stopped instead of exiting'''
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   145
    if os.WIFEXITED(code):
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   146
        return os.WEXITSTATUS(code)
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   147
    elif os.WIFSIGNALED(code):
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   148
        return -os.WTERMSIG(code)
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   149
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   150
if os.name != 'nt':
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   151
    _platformworker = _posixworker
18707
d1a2b086d058 worker: on error, exit similarly to the first failing worker
Bryan O'Sullivan <bryano@fb.com>
parents: 18638
diff changeset
   152
    _exitstatus = _posixexitstatus
18638
047110c0e2a8 worker: allow a function to be run in multiple worker processes
Bryan O'Sullivan <bryano@fb.com>
parents: 18637
diff changeset
   153
18637
ac4dbceeb14a worker: partition a list (of tasks) into equal-sized chunks
Bryan O'Sullivan <bryano@fb.com>
parents: 18636
diff changeset
   154
def partition(lst, nslices):
28181
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   155
    '''partition a list into N slices of roughly equal size
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   156
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   157
    The current strategy takes every Nth element from the input. If
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   158
    we ever write workers that need to preserve grouping in input
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   159
    we should consider allowing callers to specify a partition strategy.
28292
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   160
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   161
    mpm is not a fan of this partitioning strategy when files are involved.
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   162
    In his words:
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   163
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   164
        Single-threaded Mercurial makes a point of creating and visiting
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   165
        files in a fixed order (alphabetical). When creating files in order,
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   166
        a typical filesystem is likely to allocate them on nearby regions on
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   167
        disk. Thus, when revisiting in the same order, locality is maximized
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   168
        and various forms of OS and disk-level caching and read-ahead get a
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   169
        chance to work.
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   170
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   171
        This effect can be quite significant on spinning disks. I discovered it
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   172
        circa Mercurial v0.4 when revlogs were named by hashes of filenames.
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   173
        Tarring a repo and copying it to another disk effectively randomized
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   174
        the revlog ordering on disk by sorting the revlogs by hash and suddenly
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   175
        performance of my kernel checkout benchmark dropped by ~10x because the
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   176
        "working set" of sectors visited no longer fit in the drive's cache and
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   177
        the workload switched from streaming to random I/O.
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   178
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   179
        What we should really be doing is have workers read filenames from a
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   180
        ordered queue. This preserves locality and also keeps any worker from
3eb7faf6d958 worker: document poor partitioning scheme impact
Gregory Szorc <gregory.szorc@gmail.com>
parents: 28181
diff changeset
   181
        getting more than one file out of balance.
28181
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   182
    '''
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   183
    for i in range(nslices):
f8efc8a3a991 worker: change partition strategy to every Nth element
Gregory Szorc <gregory.szorc@gmail.com>
parents: 26587
diff changeset
   184
        yield lst[i::nslices]