Chromium Code Reviews
chromiumcodereview-hr@appspot.gserviceaccount.com (chromiumcodereview-hr) | Please choose your nickname with Settings | Help | Chromium Project | Gerrit Changes | Sign out
(1)

Side by Side Diff: build/android/pylib/utils/parallelizer.py

Issue 290573004: [Android] Support generic parallel execution across devices. (Closed) Base URL: https://chromium.googlesource.com/chromium/src.git@master
Patch Set: fix the parallelizer tests Created 6 years, 7 months ago
Use n/p to move between diff chunks; N/P to move between comments. Draft comments are only viewable by you.
Jump to:
View unified diff | Download patch
OLDNEW
(Empty)
1 # Copyright 2014 The Chromium Authors. All rights reserved.
2 # Use of this source code is governed by a BSD-style license that can be
3 # found in the LICENSE file.
4
5 """ Wrapper that allows method execution in parallel.
6
7 This class wraps a list of objects of the same type, emulates their
8 interface, and executes any functions called on the objects in parallel
9 in ReraiserThreads.
10
11 This means that, given a list of objects:
12
13 class Foo:
14 def __init__(self):
15 self.baz = Baz()
16
17 def bar(self, my_param):
18 // do something
19
20 list_of_foos = [Foo(1), Foo(2), Foo(3)]
21
22 we can take a sequential operation on that list of objects:
23
24 for f in list_of_foos:
25 f.bar('Hello')
26
27 and run it in parallel across all of the objects:
28
29 Parallelizer(list_of_foos).bar('Hello')
30
31 It can also handle (non-method) attributes of objects, so that this:
32
33 for f in list_of_foos:
34 f.baz.myBazMethod()
35
36 can be run in parallel with:
37
38 Parallelizer(list_of_foos).baz.myBazMethod()
39
40 Because it emulates the interface of the wrapped objects, a Parallelizer
41 can be passed to a method or function that takes objects of that type:
42
43 def DoesSomethingWithFoo(the_foo):
44 the_foo.bar('Hello')
45 the_foo.bar('world')
46 the_foo.baz.myBazMethod
47
48 DoesSomethingWithFoo(Parallelizer(list_of_foos))
49
50 Note that this class spins up a thread for each object. Using this class
51 to parallelize operations that are already fast will incur a net performance
52 penalty.
53
54 """
55 # pylint: disable=W0613
56
57 from pylib.utils import reraiser_thread
58 from pylib.utils import watchdog_timer
59
60 _DEFAULT_TIMEOUT = 30
61 _DEFAULT_RETRIES = 3
62
63
64 class Parallelizer(object):
65 """Allows parallel execution of method calls across a group of objects."""
66
67 def __init__(self, objs):
68 assert (objs is not None and len(objs) > 0), (
69 "Passed empty list to 'Parallelizer'")
70 self._orig_objs = objs
71 self._objs = objs
72
73 def __getattr__(self, name):
74 """Emulate getting the |name| attribute of |self|.
75
76 Args:
77 name: The name of the attribute to retrieve.
78 Returns:
79 A Parallelizer emulating the |name| attribute of |self|.
80 """
81 self.pGet(None)
82
83 r = Parallelizer(self._orig_objs)
84 r._objs = [getattr(o, name) for o in self._objs]
85 return r
86
87 def __getitem__(self, index):
88 """Emulate getting the value of |self| at |index|.
89
90 Returns:
91 A Parallelizer emulating the value of |self| at |index|.
92 """
93 self.pGet(None)
94
95 r = Parallelizer(self._orig_objs)
96 r._objs = [o[index] for o in self._objs]
97 return r
98
99 def __call__(self, *args, **kwargs):
100 """Emulate calling |self| with |args| and |kwargs|.
101
102 Note that this call is asynchronous. Call pFinish on the return value to
103 block until the call finishes.
104
105 Returns:
106 A Parallelizer wrapping the ReraiserThreadGroup running the call in
107 parallel.
108 Raises:
109 AttributeError if the wrapped objects aren't callable.
110 """
111 self.pGet(None)
112
113 if not self._objs:
114 raise AttributeError('Nothing to call.')
115 for o in self._objs:
116 if not callable(o):
117 raise AttributeError("'%s' is not callable" % o.__name__)
118
119 r = Parallelizer(self._orig_objs)
120 r._objs = reraiser_thread.ReraiserThreadGroup(
121 [reraiser_thread.ReraiserThread(
122 o, args=args, kwargs=kwargs,
123 name='%s.%s' % (str(d), o.__name__))
124 for d, o in zip(self._orig_objs, self._objs)])
125 r._objs.StartAll() # pylint: disable=W0212
126 return r
127
128 def pFinish(self, timeout):
129 """Finish any outstanding asynchronous operations.
130
131 Args:
132 timeout: The maximum number of seconds to wait for an individual
133 result to return, or None to wait forever.
134 Returns:
135 self, now emulating the return values.
136 """
137 self._assertNoShadow('pFinish')
138 if isinstance(self._objs, reraiser_thread.ReraiserThreadGroup):
139 self._objs.JoinAll()
140 self._objs = self._objs.GetAllReturnValues(
141 watchdog_timer.WatchdogTimer(timeout))
142 return self
143
144 def pGet(self, timeout):
145 """Get the current wrapped objects.
146
147 Args:
148 timeout: Same as |pFinish|.
149 Returns:
150 A list of the results, in order of the provided devices.
151 Raises:
152 Any exception raised by any of the called functions.
153 """
154 self._assertNoShadow('pGet')
155 self.pFinish(timeout)
156 return self._objs
157
158 def _assertNoShadow(self, attr_name):
159 """Ensures that |attr_name| isn't shadowing part of the wrapped obejcts.
160
161 If the wrapped objects _do_ have an |attr_name| attribute, it will be
162 inaccessible to clients.
163
164 Args:
165 attr_name: The attribute to check.
166 Raises:
167 AssertionError if the wrapped objects have an attribute named 'attr_name'
168 or '_assertNoShadow'.
169 """
170 if isinstance(self._objs, reraiser_thread.ReraiserThreadGroup):
171 assert(not hasattr(self._objs, '_assertNoShadow'))
172 assert(not hasattr(self._objs, 'pGet'))
173 else:
174 assert(not any(hasattr(o, '_assertNoShadow') for o in self._objs))
175 assert(not any(hasattr(o, 'pGet') for o in self._objs))
176
177
178 class SyncParallelizer(Parallelizer):
179 """A Parallelizer that blocks on function calls."""
180
181 #override
182 def __call__(self, *args, **kwargs):
183 """Emulate calling |self| with |args| and |kwargs|.
184
185 Note that this call is synchronous.
186
187 Returns:
188 A Parallelizer emulating the value returned from calling |self| with
189 |args| and |kwargs|.
190 Raises:
191 AttributeError if the wrapped objects aren't callable.
192 """
193 r = super(SyncParallelizer, self).__call__(*args, **kwargs)
194 r.pFinish(None)
195 return r
196
OLDNEW
« no previous file with comments | « build/android/pylib/device/device_utils.py ('k') | build/android/pylib/utils/parallelizer_test.py » ('j') | no next file with comments »

Powered by Google App Engine
This is Rietveld 408576698