Mercurial > hg
view tests/test-lock.py @ 30212:260af19891f2
changegroup: increase write buffer size to 128k
By default, Python defers to the operating system for choosing the
default buffer size on opened files. On my Linux machine, the default
is 4k, which is really small for 2016.
This patch bumps the write buffer size when writing
changegroups/bundles to 128k. This matches the 128k read buffer
we already use on revlogs.
It's worth noting that this only impacts when writing to an explicit
file (such as during `hg bundle`). Buffers when writing to bundle
files via the repo vfs or to a temporary file are not impacted.
When producing a none-v2 bundle file of the mozilla-unified repository,
this change caused the number of write() system calls to drop from
952,449 to 29,788. After this change, the most frequent system
calls are fstat(), read(), lseek(), and open(). There were
2,523,672 system calls after this patch (so a net decrease of
~950k is statistically significant).
This change shows no performance change on my system. But I have a
high-end system with a fast SSD. It is quite possible this change
will have a significant impact on network file systems, where
extra network round trips due to excessive I/O system calls could
introduce significant latency.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 16 Oct 2016 13:35:23 -0700 |
parents | 14033c5dd261 |
children | e067741d4607 |
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from __future__ import absolute_import import copy import os import silenttestrunner import tempfile import types import unittest from mercurial import ( error, lock, scmutil, ) testlockname = 'testlock' # work around http://bugs.python.org/issue1515 if types.MethodType not in copy._deepcopy_dispatch: def _deepcopy_method(x, memo): return type(x)(x.im_func, copy.deepcopy(x.im_self, memo), x.im_class) copy._deepcopy_dispatch[types.MethodType] = _deepcopy_method class lockwrapper(lock.lock): def __init__(self, pidoffset, *args, **kwargs): # lock.lock.__init__() calls lock(), so the pidoffset assignment needs # to be earlier self._pidoffset = pidoffset super(lockwrapper, self).__init__(*args, **kwargs) def _getpid(self): return super(lockwrapper, self)._getpid() + self._pidoffset class teststate(object): def __init__(self, testcase, dir, pidoffset=0): self._testcase = testcase self._acquirecalled = False self._releasecalled = False self._postreleasecalled = False self.vfs = scmutil.vfs(dir, audit=False) self._pidoffset = pidoffset def makelock(self, *args, **kwargs): l = lockwrapper(self._pidoffset, self.vfs, testlockname, releasefn=self.releasefn, acquirefn=self.acquirefn, *args, **kwargs) l.postrelease.append(self.postreleasefn) return l def acquirefn(self): self._acquirecalled = True def releasefn(self): self._releasecalled = True def postreleasefn(self): self._postreleasecalled = True def assertacquirecalled(self, called): self._testcase.assertEqual( self._acquirecalled, called, 'expected acquire to be %s but was actually %s' % ( self._tocalled(called), self._tocalled(self._acquirecalled), )) def resetacquirefn(self): self._acquirecalled = False def assertreleasecalled(self, called): self._testcase.assertEqual( self._releasecalled, called, 'expected release to be %s but was actually %s' % ( self._tocalled(called), self._tocalled(self._releasecalled), )) def assertpostreleasecalled(self, called): self._testcase.assertEqual( self._postreleasecalled, called, 'expected postrelease to be %s but was actually %s' % ( self._tocalled(called), self._tocalled(self._postreleasecalled), )) def assertlockexists(self, exists): actual = self.vfs.lexists(testlockname) self._testcase.assertEqual( actual, exists, 'expected lock to %s but actually did %s' % ( self._toexists(exists), self._toexists(actual), )) def _tocalled(self, called): if called: return 'called' else: return 'not called' def _toexists(self, exists): if exists: return 'exist' else: return 'not exist' class testlock(unittest.TestCase): def testlock(self): state = teststate(self, tempfile.mkdtemp(dir=os.getcwd())) lock = state.makelock() state.assertacquirecalled(True) lock.release() state.assertreleasecalled(True) state.assertpostreleasecalled(True) state.assertlockexists(False) def testrecursivelock(self): state = teststate(self, tempfile.mkdtemp(dir=os.getcwd())) lock = state.makelock() state.assertacquirecalled(True) state.resetacquirefn() lock.lock() # recursive lock should not call acquirefn again state.assertacquirecalled(False) lock.release() # brings lock refcount down from 2 to 1 state.assertreleasecalled(False) state.assertpostreleasecalled(False) state.assertlockexists(True) lock.release() # releases the lock state.assertreleasecalled(True) state.assertpostreleasecalled(True) state.assertlockexists(False) def testlockfork(self): state = teststate(self, tempfile.mkdtemp(dir=os.getcwd())) lock = state.makelock() state.assertacquirecalled(True) # fake a fork forklock = copy.deepcopy(lock) forklock._pidoffset = 1 forklock.release() state.assertreleasecalled(False) state.assertpostreleasecalled(False) state.assertlockexists(True) # release the actual lock lock.release() state.assertreleasecalled(True) state.assertpostreleasecalled(True) state.assertlockexists(False) def testinheritlock(self): d = tempfile.mkdtemp(dir=os.getcwd()) parentstate = teststate(self, d) parentlock = parentstate.makelock() parentstate.assertacquirecalled(True) # set up lock inheritance with parentlock.inherit() as lockname: parentstate.assertreleasecalled(True) parentstate.assertpostreleasecalled(False) parentstate.assertlockexists(True) childstate = teststate(self, d, pidoffset=1) childlock = childstate.makelock(parentlock=lockname) childstate.assertacquirecalled(True) childlock.release() childstate.assertreleasecalled(True) childstate.assertpostreleasecalled(False) childstate.assertlockexists(True) parentstate.resetacquirefn() parentstate.assertacquirecalled(True) parentlock.release() parentstate.assertreleasecalled(True) parentstate.assertpostreleasecalled(True) parentstate.assertlockexists(False) def testmultilock(self): d = tempfile.mkdtemp(dir=os.getcwd()) state0 = teststate(self, d) lock0 = state0.makelock() state0.assertacquirecalled(True) with lock0.inherit() as lock0name: state0.assertreleasecalled(True) state0.assertpostreleasecalled(False) state0.assertlockexists(True) state1 = teststate(self, d, pidoffset=1) lock1 = state1.makelock(parentlock=lock0name) state1.assertacquirecalled(True) # from within lock1, acquire another lock with lock1.inherit() as lock1name: # since the file on disk is lock0's this should have the same # name self.assertEqual(lock0name, lock1name) state2 = teststate(self, d, pidoffset=2) lock2 = state2.makelock(parentlock=lock1name) state2.assertacquirecalled(True) lock2.release() state2.assertreleasecalled(True) state2.assertpostreleasecalled(False) state2.assertlockexists(True) state1.resetacquirefn() state1.assertacquirecalled(True) lock1.release() state1.assertreleasecalled(True) state1.assertpostreleasecalled(False) state1.assertlockexists(True) lock0.release() def testinheritlockfork(self): d = tempfile.mkdtemp(dir=os.getcwd()) parentstate = teststate(self, d) parentlock = parentstate.makelock() parentstate.assertacquirecalled(True) # set up lock inheritance with parentlock.inherit() as lockname: childstate = teststate(self, d, pidoffset=1) childlock = childstate.makelock(parentlock=lockname) childstate.assertacquirecalled(True) # fork the child lock forkchildlock = copy.deepcopy(childlock) forkchildlock._pidoffset += 1 forkchildlock.release() childstate.assertreleasecalled(False) childstate.assertpostreleasecalled(False) childstate.assertlockexists(True) # release the child lock childlock.release() childstate.assertreleasecalled(True) childstate.assertpostreleasecalled(False) childstate.assertlockexists(True) parentlock.release() def testinheritcheck(self): d = tempfile.mkdtemp(dir=os.getcwd()) state = teststate(self, d) def check(): raise error.LockInheritanceContractViolation('check failed') lock = state.makelock(inheritchecker=check) state.assertacquirecalled(True) def tryinherit(): with lock.inherit(): pass self.assertRaises(error.LockInheritanceContractViolation, tryinherit) lock.release() if __name__ == '__main__': silenttestrunner.main(__name__)