outgoing: add a simple fastpath when there is no common
This further speed up case like `hg bundle --all` for larger repository.
### data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
# benchmark.name = hg.command.bundle
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.revs = all
# benchmark.variants.type = none-streamv2
before: 316.749699
after: 311.165461 (-1.76%, -5.58)
There is further work to be done in this area like not doing any outgoing
computation in the stream case for example. however the recent changes already
gives use a large win for a small amount of local work.
### benchmark.name = hg.command.bundle
# bin-env-vars.hg.flavor = default
# bin-env-vars.hg.py-re2-module = default
# benchmark.variants.revs = all
# benchmark.variants.type = none-streamv2
## data-env-vars.name = mercurial-public-2024-03-22-zstd-sparse-revlog
pre-%ln-change: 1.263859
the-%ln-change: 0.700229 (-44.60%, -0.56)
prev-changeset: 0.496050 (-60.75%, -0.77)
this-changeset: 0.495243 (-60.81%, -0.77)
## data-env-vars.name = tryton-public-2024-03-22-zstd-sparse-revlog
pre-%ln-change: 2.975765
the-%ln-change: 1.870798 (-37.13%, -1.10)
prev-changeset: 1.461583 (-50.88%, -1.51)
this-changeset: 1.469185 (-50.63%, -1.51)
## data-env-vars.name = pypy-2024-03-22-zstd-sparse-revlog
pre-%ln-change: 4.540080
the-%ln-change: 3.401700 (-25.07%, -1.14)
prev-changeset: 2.915810 (-35.78%, -1.62)
this-changeset: 2.911643 (-35.87%, -1.63)
## data-env-vars.name = heptapod-public-2024-03-25-zstd-sparse-revlog
pre-%ln-change: 10.138396
the-%ln-change: 7.750458 (-23.55%, -2.39)
prev-changeset: 6.665565 (-34.25%, -3.47)
this-changeset: 6.672078 (-34.19%, -3.47)
## data-env-vars.name = mozilla-try-2023-03-22-zstd-sparse-revlog
pre-%ln-change: 399.484481
the-%ln-change: 346.508952 (-13.26%, -52.98)
prev-changeset: 316.749699 (-20.71%, -82.73)
this-changeset: 311.165461 (-22.11%, -88.32)
# repocache.py - in-memory repository cache for long-running services
#
# Copyright 2018 Yuya Nishihara <yuya@tcha.org>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
import collections
import gc
import threading
from . import (
error,
hg,
obsolete,
scmutil,
util,
)
class repoloader:
"""Load repositories in background thread
This is designed for a forking server. A cached repo cannot be obtained
until the server fork()s a worker and the loader thread stops.
"""
def __init__(self, ui, maxlen):
self._ui = ui.copy()
self._cache = util.lrucachedict(max=maxlen)
# use deque and Event instead of Queue since deque can discard
# old items to keep at most maxlen items.
self._inqueue = collections.deque(maxlen=maxlen)
self._accepting = False
self._newentry = threading.Event()
self._thread = None
def start(self):
assert not self._thread
if self._inqueue.maxlen == 0:
# no need to spawn loader thread as the cache is disabled
return
self._accepting = True
self._thread = threading.Thread(target=self._mainloop)
self._thread.start()
def stop(self):
if not self._thread:
return
self._accepting = False
self._newentry.set()
self._thread.join()
self._thread = None
self._cache.clear()
self._inqueue.clear()
def load(self, path):
"""Request to load the specified repository in background"""
self._inqueue.append(path)
self._newentry.set()
def get(self, path):
"""Return a cached repo if available
This function must be called after fork(), where the loader thread
is stopped. Otherwise, the returned repo might be updated by the
loader thread.
"""
if self._thread and self._thread.is_alive():
raise error.ProgrammingError(
b'cannot obtain cached repo while loader is active'
)
return self._cache.peek(path, None)
def _mainloop(self):
while self._accepting:
# Avoid heavy GC after fork(), which would cancel the benefit of
# COW. We assume that GIL is acquired while GC is underway in the
# loader thread. If that isn't true, we might have to move
# gc.collect() to the main thread so that fork() would never stop
# the thread where GC is in progress.
gc.collect()
self._newentry.wait()
while self._accepting:
self._newentry.clear()
try:
path = self._inqueue.popleft()
except IndexError:
break
scmutil.callcatch(self._ui, lambda: self._load(path))
def _load(self, path):
start = util.timer()
# TODO: repo should be recreated if storage configuration changed
try:
# pop before loading so inconsistent state wouldn't be exposed
repo = self._cache.pop(path)
except KeyError:
repo = hg.repository(self._ui, path).unfiltered()
_warmupcache(repo)
repo.ui.log(
b'repocache',
b'loaded repo into cache: %s (in %.3fs)\n',
path,
util.timer() - start,
)
self._cache.insert(path, repo)
# TODO: think about proper API of preloading cache
def _warmupcache(repo):
repo.invalidateall()
repo.changelog
repo.obsstore._all
repo.obsstore.successors
repo.obsstore.predecessors
repo.obsstore.children
for name in obsolete.cachefuncs:
obsolete.getrevs(repo, name)
# ensure the phase cache is fully initialized
repo._phasecache.phase(repo, repo.changelog.tiprev())
# TODO: think about proper API of attaching preloaded attributes
def copycache(srcrepo, destrepo):
"""Copy cached attributes from srcrepo to destrepo"""
destfilecache = destrepo._filecache
srcfilecache = srcrepo._filecache
if b'changelog' in srcfilecache:
destfilecache[b'changelog'] = ce = srcfilecache[b'changelog']
ce.obj.opener = ce.obj._inner.opener = destrepo.svfs
if b'obsstore' in srcfilecache:
destfilecache[b'obsstore'] = ce = srcfilecache[b'obsstore']
ce.obj.svfs = destrepo.svfs
if b'_phasecache' in srcfilecache:
destfilecache[b'_phasecache'] = ce = srcfilecache[b'_phasecache']
ce.obj.opener = destrepo.svfs