exchange: improve computation of relevant markers for large repos
Compute the candidate nodes with relevant markers directly
from keys of the predecessors/successors/children dictionaries of
obsstore. This is faster than iterating over all nodes directly.
This test could be further improved for repositories with relative
few markers compared to the repository size, but this is no longer
hot already. With the current loop structure, the obshashrange use
works as well as before as it passes lists with a single node.
Adjust the interface by allowing revision lists as well as node lists.
This helps cases that computes ancestors as it reduces the
materialisation cost. Use this in _pushdiscoveryobsmarker and
_getbundleobsmarkerpart. Improve the latter further by directly using
ancestors().
Performance benchmarks show notable and welcome improvement to no-op push and
pull (that would also apply to other push/pull). This apply to push and pull
done without evolve.
### push/pull Benchmark parameter
# bin-env-vars.hg.flavor = default
# benchmark.variants.explicit-rev = none
# benchmark.variants.protocol = ssh
# benchmark.variants.revs = none
## benchmark.name = hg.command.pull
# data-env-vars.name = mercurial-devel-2024-03-22-zstd-sparse-revlog
before: 5.968537 seconds
after: 5.668507 seconds (-5.03%, -0.30)
# data-env-vars.name = tryton-devel-2024-03-22-zstd-sparse-revlog
before: 1.446232 seconds
after: 0.835553 seconds (-42.23%, -0.61)
# data-env-vars.name = netbsd-src-draft-2024-09-19-zstd-sparse-revlog
before: 5.777412 seconds
after: 2.523454 seconds (-56.32%, -3.25)
## benchmark.name = hg.command.push
# data-env-vars.name = mercurial-devel-2024-03-22-zstd-sparse-revlog
before: 6.155501 seconds
after: 5.885072 seconds (-4.39%, -0.27)
# data-env-vars.name = tryton-devel-2024-03-22-zstd-sparse-revlog
before: 1.491054 seconds
after: 0.934882 seconds (-37.30%, -0.56)
# data-env-vars.name = netbsd-src-draft-2024-09-19-zstd-sparse-revlog
before: 5.902494 seconds
after: 2.957644 seconds (-49.89%, -2.94)
There is not notable different in these result using the "rust" flavor instead
of the "default". The performance impact on the same operation when using
evolve were also tested and no impact was noted.
# discovery.py - protocol changeset discovery functions
#
# Copyright 2010 Olivia Mackall <olivia@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 annotations
import collections
from .i18n import _
from .node import short
from . import (
error,
)
def findcommonincoming(repo, remote, heads=None, force=False, audit=None):
"""Return a tuple (common, fetch, heads) used to identify the common
subset of nodes between repo and remote.
"common" is a list of (at least) the heads of the common subset.
"fetch" is a list of roots of the nodes that would be incoming, to be
supplied to changegroupsubset.
"heads" is either the supplied heads, or else the remote's heads.
"""
knownnode = repo.changelog.hasnode
search = []
fetch = set()
seen = set()
seenbranch = set()
base = set()
if not heads:
with remote.commandexecutor() as e:
heads = e.callcommand(b'heads', {}).result()
if audit is not None:
audit[b'total-roundtrips'] = 1
audit[b'total-roundtrips-heads'] = 1
audit[b'total-roundtrips-branches'] = 0
audit[b'total-roundtrips-between'] = 0
audit[b'total-queries'] = 0
audit[b'total-queries-branches'] = 0
audit[b'total-queries-between'] = 0
if repo.changelog.tip() == repo.nullid:
base.add(repo.nullid)
if heads != [repo.nullid]:
return [repo.nullid], [repo.nullid], list(heads)
return [repo.nullid], [], heads
# assume we're closer to the tip than the root
# and start by examining the heads
repo.ui.status(_(b"searching for changes\n"))
unknown = []
for h in heads:
if not knownnode(h):
unknown.append(h)
else:
base.add(h)
if not unknown:
return list(base), [], list(heads)
req = set(unknown)
reqcnt = 0
progress = repo.ui.makeprogress(_(b'searching'), unit=_(b'queries'))
# search through remote branches
# a 'branch' here is a linear segment of history, with four parts:
# head, root, first parent, second parent
# (a branch always has two parents (or none) by definition)
with remote.commandexecutor() as e:
if audit is not None:
audit[b'total-queries'] += len(unknown)
audit[b'total-queries-branches'] += len(unknown)
audit[b'total-roundtrips'] += 1
audit[b'total-roundtrips-branches'] += 1
branches = e.callcommand(b'branches', {b'nodes': unknown}).result()
unknown = collections.deque(branches)
while unknown:
r = []
while unknown:
n = unknown.popleft()
if n[0] in seen:
continue
repo.ui.debug(b"examining %s:%s\n" % (short(n[0]), short(n[1])))
if n[0] == repo.nullid: # found the end of the branch
pass
elif n in seenbranch:
repo.ui.debug(b"branch already found\n")
continue
elif n[1] and knownnode(n[1]): # do we know the base?
repo.ui.debug(
b"found incomplete branch %s:%s\n"
% (short(n[0]), short(n[1]))
)
search.append(n[0:2]) # schedule branch range for scanning
seenbranch.add(n)
else:
if n[1] not in seen and n[1] not in fetch:
if knownnode(n[2]) and knownnode(n[3]):
repo.ui.debug(b"found new changeset %s\n" % short(n[1]))
fetch.add(n[1]) # earliest unknown
for p in n[2:4]:
if knownnode(p):
base.add(p) # latest known
for p in n[2:4]:
if p not in req and not knownnode(p):
r.append(p)
req.add(p)
seen.add(n[0])
if r:
for p in range(0, len(r), 10):
reqcnt += 1
progress.increment()
if repo.ui.debugflag:
msg = b"request %d: %s\n"
msg %= (reqcnt, b" ".join(map(short, r)))
repo.ui.debug(msg)
with remote.commandexecutor() as e:
subset = r[p : p + 10]
if audit is not None:
audit[b'total-queries'] += len(subset)
audit[b'total-queries-branches'] += len(subset)
audit[b'total-roundtrips'] += 1
audit[b'total-roundtrips-branches'] += 1
branches = e.callcommand(
b'branches',
{
b'nodes': subset,
},
).result()
for b in branches:
repo.ui.debug(
b"received %s:%s\n" % (short(b[0]), short(b[1]))
)
unknown.append(b)
# do binary search on the branches we found
while search:
newsearch = []
reqcnt += 1
progress.increment()
with remote.commandexecutor() as e:
if audit is not None:
audit[b'total-queries'] += len(search)
audit[b'total-queries-between'] += len(search)
audit[b'total-roundtrips'] += 1
audit[b'total-roundtrips-between'] += 1
between = e.callcommand(b'between', {b'pairs': search}).result()
for n, l in zip(search, between):
l.append(n[1])
p = n[0]
f = 1
for i in l:
repo.ui.debug(b"narrowing %d:%d %s\n" % (f, len(l), short(i)))
if knownnode(i):
if f <= 2:
repo.ui.debug(
b"found new branch changeset %s\n" % short(p)
)
fetch.add(p)
base.add(i)
else:
repo.ui.debug(
b"narrowed branch search to %s:%s\n"
% (short(p), short(i))
)
newsearch.append((p, i))
break
p, f = i, f * 2
search = newsearch
# sanity check our fetch list
for f in fetch:
if knownnode(f):
raise error.RepoError(_(b"already have changeset ") + short(f[:4]))
base = list(base)
if base == [repo.nullid]:
if force:
repo.ui.warn(_(b"warning: repository is unrelated\n"))
else:
raise error.Abort(_(b"repository is unrelated"))
repo.ui.debug(
b"found new changesets starting at "
+ b" ".join([short(f) for f in fetch])
+ b"\n"
)
progress.complete()
repo.ui.debug(b"%d total queries\n" % reqcnt)
return base, list(fetch), heads