Mercurial > hg
view mercurial/sshpeer.py @ 26379:39d643252b9f
revlog: use existing file handle when reading during _addrevision
_addrevision() may need to read from revlogs as part of computing
deltas. Previously, we would flush existing file handles and open
a new, short-lived file handle to perform the reading.
If we have an existing file handle, it seems logical to reuse it
for reading instead of opening a new file handle. This patch
makes that the new behavior.
After this patch, revlog files are only reopened when adding
revisions if the revlog is switched from inline to non-inline.
On Linux when unbundling a bundle of the mozilla-central repo, this
patch has the following impact on system call counts:
Call Before After Delta
write 827,639 673,390 -154,249
open 700,103 684,089 -16,014
read 74,489 74,489 0
fstat 493,924 461,896 -32,028
close 249,131 233,117 -16,014
stat 242,001 242,001 0
lstat 18,676 18,676 0
lseek 20,268 20,268 0
ioctl 14,652 13,173 -1,479
TOTAL 3,180,758 2,930,679 -250,079
It's worth noting that many of the open() calls fail due to missing
files. That's why there are many more open() calls than close().
Despite the significant system call reduction, this change does not
seem to have a significant performance impact on Linux.
On Windows 10 (not a VM, on a SSD), this patch appears to reduce
unbundle time for mozilla-central from ~960s to ~920s. This isn't
as significant as I was hoping. But a decrease it is nonetheless.
Still, Windows unbundle performance is still >2x slower than Linux.
Despite the lack of significant gains, fewer system calls is fewer
system calls. If nothing else, this will narrow the focus of potential
areas to optimize in the future.
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Sun, 27 Sep 2015 16:08:18 -0700 |
parents | de7a3893ee65 |
children | 56b2bcea2529 |
line wrap: on
line source
# sshpeer.py - ssh repository proxy class for mercurial # # Copyright 2005, 2006 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 re from .i18n import _ from . import ( error, util, wireproto, ) class remotelock(object): def __init__(self, repo): self.repo = repo def release(self): self.repo.unlock() self.repo = None def __del__(self): if self.repo: self.release() def _serverquote(s): if not s: return s '''quote a string for the remote shell ... which we assume is sh''' if re.match('[a-zA-Z0-9@%_+=:,./-]*$', s): return s return "'%s'" % s.replace("'", "'\\''") def _forwardoutput(ui, pipe): """display all data currently available on pipe as remote output. This is non blocking.""" s = util.readpipe(pipe) if s: for l in s.splitlines(): ui.status(_("remote: "), l, '\n') class doublepipe(object): """Operate a side-channel pipe in addition of a main one The side-channel pipe contains server output to be forwarded to the user input. The double pipe will behave as the "main" pipe, but will ensure the content of the "side" pipe is properly processed while we wait for blocking call on the "main" pipe. If large amounts of data are read from "main", the forward will cease after the first bytes start to appear. This simplifies the implementation without affecting actual output of sshpeer too much as we rarely issue large read for data not yet emitted by the server. The main pipe is expected to be a 'bufferedinputpipe' from the util module that handle all the os specific bites. This class lives in this module because it focus on behavior specifig to the ssh protocol.""" def __init__(self, ui, main, side): self._ui = ui self._main = main self._side = side def _wait(self): """wait until some data are available on main or side return a pair of boolean (ismainready, issideready) (This will only wait for data if the setup is supported by `util.poll`) """ if getattr(self._main, 'hasbuffer', False): # getattr for classic pipe return (True, True) # main has data, assume side is worth poking at. fds = [self._main.fileno(), self._side.fileno()] try: act = util.poll(fds) except NotImplementedError: # non supported yet case, assume all have data. act = fds return (self._main.fileno() in act, self._side.fileno() in act) def write(self, data): return self._call('write', data) def read(self, size): return self._call('read', size) def readline(self): return self._call('readline') def _call(self, methname, data=None): """call <methname> on "main", forward output of "side" while blocking """ # data can be '' or 0 if (data is not None and not data) or self._main.closed: _forwardoutput(self._ui, self._side) return '' while True: mainready, sideready = self._wait() if sideready: _forwardoutput(self._ui, self._side) if mainready: meth = getattr(self._main, methname) if data is None: return meth() else: return meth(data) def close(self): return self._main.close() def flush(self): return self._main.flush() class sshpeer(wireproto.wirepeer): def __init__(self, ui, path, create=False): self._url = path self.ui = ui self.pipeo = self.pipei = self.pipee = None u = util.url(path, parsequery=False, parsefragment=False) if u.scheme != 'ssh' or not u.host or u.path is None: self._abort(error.RepoError(_("couldn't parse location %s") % path)) self.user = u.user if u.passwd is not None: self._abort(error.RepoError(_("password in URL not supported"))) self.host = u.host self.port = u.port self.path = u.path or "." sshcmd = self.ui.config("ui", "ssh", "ssh") remotecmd = self.ui.config("ui", "remotecmd", "hg") args = util.sshargs(sshcmd, _serverquote(self.host), _serverquote(self.user), _serverquote(self.port)) if create: cmd = '%s %s %s' % (sshcmd, args, util.shellquote("%s init %s" % (_serverquote(remotecmd), _serverquote(self.path)))) ui.debug('running %s\n' % cmd) res = ui.system(cmd) if res != 0: self._abort(error.RepoError(_("could not create remote repo"))) self._validaterepo(sshcmd, args, remotecmd) def url(self): return self._url def _validaterepo(self, sshcmd, args, remotecmd): # cleanup up previous run self.cleanup() cmd = '%s %s %s' % (sshcmd, args, util.shellquote("%s -R %s serve --stdio" % (_serverquote(remotecmd), _serverquote(self.path)))) self.ui.debug('running %s\n' % cmd) cmd = util.quotecommand(cmd) # while self.subprocess isn't used, having it allows the subprocess to # to clean up correctly later # # no buffer allow the use of 'select' # feel free to remove buffering and select usage when we ultimately # move to threading. sub = util.popen4(cmd, bufsize=0) self.pipeo, self.pipei, self.pipee, self.subprocess = sub self.pipei = util.bufferedinputpipe(self.pipei) self.pipei = doublepipe(self.ui, self.pipei, self.pipee) self.pipeo = doublepipe(self.ui, self.pipeo, self.pipee) # skip any noise generated by remote shell self._callstream("hello") r = self._callstream("between", pairs=("%s-%s" % ("0"*40, "0"*40))) lines = ["", "dummy"] max_noise = 500 while lines[-1] and max_noise: l = r.readline() self.readerr() if lines[-1] == "1\n" and l == "\n": break if l: self.ui.debug("remote: ", l) lines.append(l) max_noise -= 1 else: self._abort(error.RepoError(_('no suitable response from ' 'remote hg'))) self._caps = set() for l in reversed(lines): if l.startswith("capabilities:"): self._caps.update(l[:-1].split(":")[1].split()) break def _capabilities(self): return self._caps def readerr(self): _forwardoutput(self.ui, self.pipee) def _abort(self, exception): self.cleanup() raise exception def cleanup(self): if self.pipeo is None: return self.pipeo.close() self.pipei.close() try: # read the error descriptor until EOF for l in self.pipee: self.ui.status(_("remote: "), l) except (IOError, ValueError): pass self.pipee.close() __del__ = cleanup def _callstream(self, cmd, **args): self.ui.debug("sending %s command\n" % cmd) self.pipeo.write("%s\n" % cmd) _func, names = wireproto.commands[cmd] keys = names.split() wireargs = {} for k in keys: if k == '*': wireargs['*'] = args break else: wireargs[k] = args[k] del args[k] for k, v in sorted(wireargs.iteritems()): self.pipeo.write("%s %d\n" % (k, len(v))) if isinstance(v, dict): for dk, dv in v.iteritems(): self.pipeo.write("%s %d\n" % (dk, len(dv))) self.pipeo.write(dv) else: self.pipeo.write(v) self.pipeo.flush() return self.pipei def _callcompressable(self, cmd, **args): return self._callstream(cmd, **args) def _call(self, cmd, **args): self._callstream(cmd, **args) return self._recv() def _callpush(self, cmd, fp, **args): r = self._call(cmd, **args) if r: return '', r while True: d = fp.read(4096) if not d: break self._send(d) self._send("", flush=True) r = self._recv() if r: return '', r return self._recv(), '' def _calltwowaystream(self, cmd, fp, **args): r = self._call(cmd, **args) if r: # XXX needs to be made better raise util.Abort('unexpected remote reply: %s' % r) while True: d = fp.read(4096) if not d: break self._send(d) self._send("", flush=True) return self.pipei def _recv(self): l = self.pipei.readline() if l == '\n': self.readerr() msg = _('check previous remote output') self._abort(error.OutOfBandError(hint=msg)) self.readerr() try: l = int(l) except ValueError: self._abort(error.ResponseError(_("unexpected response:"), l)) return self.pipei.read(l) def _send(self, data, flush=False): self.pipeo.write("%d\n" % len(data)) if data: self.pipeo.write(data) if flush: self.pipeo.flush() self.readerr() def lock(self): self._call("lock") return remotelock(self) def unlock(self): self._call("unlock") def addchangegroup(self, cg, source, url, lock=None): '''Send a changegroup to the remote server. Return an integer similar to unbundle(). DEPRECATED, since it requires locking the remote.''' d = self._call("addchangegroup") if d: self._abort(error.RepoError(_("push refused: %s") % d)) while True: d = cg.read(4096) if not d: break self.pipeo.write(d) self.readerr() self.pipeo.flush() self.readerr() r = self._recv() if not r: return 1 try: return int(r) except ValueError: self._abort(error.ResponseError(_("unexpected response:"), r)) instance = sshpeer