Mercurial > hg
view mercurial/hook.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 | ea1fec3e9aba |
children | a1259e502bdf |
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# hook.py - hook support for mercurial # # Copyright 2007 Matt Mackall <mpm@selenic.com> # # 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 import os import sys import time from .i18n import _ from . import ( demandimport, error, extensions, util, ) def _pythonhook(ui, repo, name, hname, funcname, args, throw): '''call python hook. hook is callable object, looked up as name in python module. if callable returns "true", hook fails, else passes. if hook raises exception, treated as hook failure. exception propagates if throw is "true". reason for "true" meaning "hook failed" is so that unmodified commands (e.g. mercurial.commands.update) can be run as hooks without wrappers to convert return values.''' if callable(funcname): obj = funcname funcname = obj.__module__ + "." + obj.__name__ else: d = funcname.rfind('.') if d == -1: raise error.HookLoadError( _('%s hook is invalid: "%s" not in a module') % (hname, funcname)) modname = funcname[:d] oldpaths = sys.path if util.mainfrozen(): # binary installs require sys.path manipulation modpath, modfile = os.path.split(modname) if modpath and modfile: sys.path = sys.path[:] + [modpath] modname = modfile with demandimport.deactivated(): try: obj = __import__(modname) except (ImportError, SyntaxError): e1 = sys.exc_info() try: # extensions are loaded with hgext_ prefix obj = __import__("hgext_%s" % modname) except (ImportError, SyntaxError): e2 = sys.exc_info() if ui.tracebackflag: ui.warn(_('exception from first failed import ' 'attempt:\n')) ui.traceback(e1) if ui.tracebackflag: ui.warn(_('exception from second failed import ' 'attempt:\n')) ui.traceback(e2) if not ui.tracebackflag: tracebackhint = _( 'run with --traceback for stack trace') else: tracebackhint = None raise error.HookLoadError( _('%s hook is invalid: import of "%s" failed') % (hname, modname), hint=tracebackhint) sys.path = oldpaths try: for p in funcname.split('.')[1:]: obj = getattr(obj, p) except AttributeError: raise error.HookLoadError( _('%s hook is invalid: "%s" is not defined') % (hname, funcname)) if not callable(obj): raise error.HookLoadError( _('%s hook is invalid: "%s" is not callable') % (hname, funcname)) ui.note(_("calling hook %s: %s\n") % (hname, funcname)) starttime = time.time() try: # redirect IO descriptors to the ui descriptors so hooks # that write directly to these don't mess up the command # protocol when running through the command server old = sys.stdout, sys.stderr, sys.stdin sys.stdout, sys.stderr, sys.stdin = ui.fout, ui.ferr, ui.fin r = obj(ui=ui, repo=repo, hooktype=name, **args) except Exception as exc: if isinstance(exc, error.Abort): ui.warn(_('error: %s hook failed: %s\n') % (hname, exc.args[0])) else: ui.warn(_('error: %s hook raised an exception: ' '%s\n') % (hname, exc)) if throw: raise if not ui.tracebackflag: ui.warn(_('(run with --traceback for stack trace)\n')) ui.traceback() return True, True finally: sys.stdout, sys.stderr, sys.stdin = old duration = time.time() - starttime ui.log('pythonhook', 'pythonhook-%s: %s finished in %0.2f seconds\n', name, funcname, duration) if r: if throw: raise error.HookAbort(_('%s hook failed') % hname) ui.warn(_('warning: %s hook failed\n') % hname) return r, False def _exthook(ui, repo, name, cmd, args, throw): ui.note(_("running hook %s: %s\n") % (name, cmd)) starttime = time.time() env = {} # make in-memory changes visible to external process if repo is not None: tr = repo.currenttransaction() repo.dirstate.write(tr) if tr and tr.writepending(): env['HG_PENDING'] = repo.root for k, v in args.iteritems(): if callable(v): v = v() if isinstance(v, dict): # make the dictionary element order stable across Python # implementations v = ('{' + ', '.join('%r: %r' % i for i in sorted(v.iteritems())) + '}') env['HG_' + k.upper()] = v if repo: cwd = repo.root else: cwd = os.getcwd() r = ui.system(cmd, environ=env, cwd=cwd) duration = time.time() - starttime ui.log('exthook', 'exthook-%s: %s finished in %0.2f seconds\n', name, cmd, duration) if r: desc, r = util.explainexit(r) if throw: raise error.HookAbort(_('%s hook %s') % (name, desc)) ui.warn(_('warning: %s hook %s\n') % (name, desc)) return r # represent an untrusted hook command _fromuntrusted = object() def _allhooks(ui): """return a list of (hook-id, cmd) pairs sorted by priority""" hooks = _hookitems(ui) # Be careful in this section, propagating the real commands from untrusted # sources would create a security vulnerability, make sure anything altered # in that section uses "_fromuntrusted" as its command. untrustedhooks = _hookitems(ui, _untrusted=True) for name, value in untrustedhooks.items(): trustedvalue = hooks.get(name, (None, None, name, _fromuntrusted)) if value != trustedvalue: (lp, lo, lk, lv) = trustedvalue hooks[name] = (lp, lo, lk, _fromuntrusted) # (end of the security sensitive section) return [(k, v) for p, o, k, v in sorted(hooks.values())] def _hookitems(ui, _untrusted=False): """return all hooks items ready to be sorted""" hooks = {} for name, cmd in ui.configitems('hooks', untrusted=_untrusted): if not name.startswith('priority'): priority = ui.configint('hooks', 'priority.%s' % name, 0) hooks[name] = (-priority, len(hooks), name, cmd) return hooks _redirect = False def redirect(state): global _redirect _redirect = state def hook(ui, repo, name, throw=False, **args): if not ui.callhooks: return False hooks = [] for hname, cmd in _allhooks(ui): if hname.split('.')[0] == name and cmd: hooks.append((hname, cmd)) res = runhooks(ui, repo, name, hooks, throw=throw, **args) r = False for hname, cmd in hooks: r = res[hname][0] or r return r def runhooks(ui, repo, name, hooks, throw=False, **args): res = {} oldstdout = -1 try: for hname, cmd in hooks: if oldstdout == -1 and _redirect: try: stdoutno = sys.__stdout__.fileno() stderrno = sys.__stderr__.fileno() # temporarily redirect stdout to stderr, if possible if stdoutno >= 0 and stderrno >= 0: sys.__stdout__.flush() oldstdout = os.dup(stdoutno) os.dup2(stderrno, stdoutno) except (OSError, AttributeError): # files seem to be bogus, give up on redirecting (WSGI, etc) pass if cmd is _fromuntrusted: if throw: raise error.HookAbort( _('untrusted hook %s not executed') % name, hint = _("see 'hg help config.trusted'")) ui.warn(_('warning: untrusted hook %s not executed\n') % name) r = 1 raised = False elif callable(cmd): r, raised = _pythonhook(ui, repo, name, hname, cmd, args, throw) elif cmd.startswith('python:'): if cmd.count(':') >= 2: path, cmd = cmd[7:].rsplit(':', 1) path = util.expandpath(path) if repo: path = os.path.join(repo.root, path) try: mod = extensions.loadpath(path, 'hghook.%s' % hname) except Exception: ui.write(_("loading %s hook failed:\n") % hname) raise hookfn = getattr(mod, cmd) else: hookfn = cmd[7:].strip() r, raised = _pythonhook(ui, repo, name, hname, hookfn, args, throw) else: r = _exthook(ui, repo, hname, cmd, args, throw) raised = False res[hname] = r, raised # The stderr is fully buffered on Windows when connected to a pipe. # A forcible flush is required to make small stderr data in the # remote side available to the client immediately. sys.stderr.flush() finally: if _redirect and oldstdout >= 0: os.dup2(oldstdout, stdoutno) os.close(oldstdout) return res