Mercurial > hg
view mercurial/registrar.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 | 6ffb7e0249f4 |
children | 318a24b52eeb |
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# registrar.py - utilities to register function for specific purpose # # Copyright FUJIWARA Katsunori <foozy@lares.dti.ne.jp> and others # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import from . import ( pycompat, util, ) class _funcregistrarbase(object): """Base of decorator to register a fuction for specific purpose This decorator stores decorated functions into own dict 'table'. The least derived class can be defined by overriding 'formatdoc', for example:: class keyword(_funcregistrarbase): _docformat = ":%s: %s" This should be used as below: keyword = registrar.keyword() @keyword('bar') def barfunc(*args, **kwargs): '''Explanation of bar keyword .... ''' pass In this case: - 'barfunc' is stored as 'bar' in '_table' of an instance 'keyword' above - 'barfunc.__doc__' becomes ":bar: Explanation of bar keyword" """ def __init__(self, table=None): if table is None: self._table = {} else: self._table = table def __call__(self, decl, *args, **kwargs): return lambda func: self._doregister(func, decl, *args, **kwargs) def _doregister(self, func, decl, *args, **kwargs): name = self._getname(decl) if func.__doc__ and not util.safehasattr(func, '_origdoc'): doc = func.__doc__.strip() func._origdoc = doc func.__doc__ = self._formatdoc(decl, doc) self._table[name] = func self._extrasetup(name, func, *args, **kwargs) return func def _parsefuncdecl(self, decl): """Parse function declaration and return the name of function in it """ i = decl.find('(') if i >= 0: return decl[:i] else: return decl def _getname(self, decl): """Return the name of the registered function from decl Derived class should override this, if it allows more descriptive 'decl' string than just a name. """ return decl _docformat = None def _formatdoc(self, decl, doc): """Return formatted document of the registered function for help 'doc' is '__doc__.strip()' of the registered function. """ return self._docformat % (decl, doc) def _extrasetup(self, name, func): """Execute exra setup for registered function, if needed """ pass class revsetpredicate(_funcregistrarbase): """Decorator to register revset predicate Usage:: revsetpredicate = registrar.revsetpredicate() @revsetpredicate('mypredicate(arg1, arg2[, arg3])') def mypredicatefunc(repo, subset, x): '''Explanation of this revset predicate .... ''' pass The first string argument is used also in online help. Optional argument 'safe' indicates whether a predicate is safe for DoS attack (False by default). Optional argument 'takeorder' indicates whether a predicate function takes ordering policy as the last argument. 'revsetpredicate' instance in example above can be used to decorate multiple functions. Decorated functions are registered automatically at loading extension, if an instance named as 'revsetpredicate' is used for decorating in extension. Otherwise, explicit 'revset.loadpredicate()' is needed. """ _getname = _funcregistrarbase._parsefuncdecl _docformat = pycompat.sysstr("``%s``\n %s") def _extrasetup(self, name, func, safe=False, takeorder=False): func._safe = safe func._takeorder = takeorder class filesetpredicate(_funcregistrarbase): """Decorator to register fileset predicate Usage:: filesetpredicate = registrar.filesetpredicate() @filesetpredicate('mypredicate()') def mypredicatefunc(mctx, x): '''Explanation of this fileset predicate .... ''' pass The first string argument is used also in online help. Optional argument 'callstatus' indicates whether a predicate implies 'matchctx.status()' at runtime or not (False, by default). Optional argument 'callexisting' indicates whether a predicate implies 'matchctx.existing()' at runtime or not (False, by default). 'filesetpredicate' instance in example above can be used to decorate multiple functions. Decorated functions are registered automatically at loading extension, if an instance named as 'filesetpredicate' is used for decorating in extension. Otherwise, explicit 'fileset.loadpredicate()' is needed. """ _getname = _funcregistrarbase._parsefuncdecl _docformat = pycompat.sysstr("``%s``\n %s") def _extrasetup(self, name, func, callstatus=False, callexisting=False): func._callstatus = callstatus func._callexisting = callexisting class _templateregistrarbase(_funcregistrarbase): """Base of decorator to register functions as template specific one """ _docformat = pycompat.sysstr(":%s: %s") class templatekeyword(_templateregistrarbase): """Decorator to register template keyword Usage:: templaetkeyword = registrar.templatekeyword() @templatekeyword('mykeyword') def mykeywordfunc(repo, ctx, templ, cache, revcache, **args): '''Explanation of this template keyword .... ''' pass The first string argument is used also in online help. 'templatekeyword' instance in example above can be used to decorate multiple functions. Decorated functions are registered automatically at loading extension, if an instance named as 'templatekeyword' is used for decorating in extension. Otherwise, explicit 'templatekw.loadkeyword()' is needed. """ class templatefilter(_templateregistrarbase): """Decorator to register template filer Usage:: templatefilter = registrar.templatefilter() @templatefilter('myfilter') def myfilterfunc(text): '''Explanation of this template filter .... ''' pass The first string argument is used also in online help. 'templatefilter' instance in example above can be used to decorate multiple functions. Decorated functions are registered automatically at loading extension, if an instance named as 'templatefilter' is used for decorating in extension. Otherwise, explicit 'templatefilters.loadkeyword()' is needed. """ class templatefunc(_templateregistrarbase): """Decorator to register template function Usage:: templatefunc = registrar.templatefunc() @templatefunc('myfunc(arg1, arg2[, arg3])') def myfuncfunc(context, mapping, args): '''Explanation of this template function .... ''' pass The first string argument is used also in online help. 'templatefunc' instance in example above can be used to decorate multiple functions. Decorated functions are registered automatically at loading extension, if an instance named as 'templatefunc' is used for decorating in extension. Otherwise, explicit 'templater.loadfunction()' is needed. """ _getname = _funcregistrarbase._parsefuncdecl