git-repo/subcmds/start.py
Kuang-che Wu 8da4861b38 subcmds: reduce multiprocessing serialization overhead
Follow the same approach as 39ffd9977e to reduce serialization overhead.

Below benchmarks are tested with 2.7k projects on my workstation
(warm cache). git tracing is disabled for benchmark.

(seconds)              | v2.48 | v2.48 | this CL | this CL
	               |       |  -j32 |         |    -j32
-----------------------------------------------------------
with clean tree state:
branches (none)        |   5.6 |   5.9 |    1.0  |    0.9
status (clean)         |  21.3 |   9.4 |   19.4  |    4.7
diff (none)            |   7.6 |   7.2 |    5.7  |    2.2
prune (none)           |   5.7 |   6.1 |    1.3  |    1.2
abandon (none)         |  19.4 |  18.6 |    0.9  |    0.8
upload (none)          |  19.7 |  18.7 |    0.9  |    0.8
forall -c true         |   7.5 |   7.6 |    0.6  |    0.6
forall -c "git log -1" |  11.3 |  11.1 |    0.6  |    0.6

with branches:
start BRANCH --all     |  21.9 |  20.3 |   13.6  |    2.6
checkout BRANCH        |  29.1 |  27.8 |    1.1  |    1.0
branches (2)           |  28.0 |  28.6 |    1.5  |    1.3
abandon BRANCH         |  29.2 |  27.5 |    9.7  |    2.2

Bug: b/371638995
Change-Id: I53989a3d1e43063587b3f52f852b1c2c56b49412
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/440221
Reviewed-by: Josip Sokcevic <sokcevic@google.com>
Tested-by: Kuang-che Wu <kcwu@google.com>
Commit-Queue: Kuang-che Wu <kcwu@google.com>
2024-10-23 23:34:34 +00:00

159 lines
4.9 KiB
Python

# Copyright (C) 2008 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import functools
from typing import NamedTuple
from command import Command
from command import DEFAULT_LOCAL_JOBS
from error import RepoExitError
from git_command import git
from git_config import IsImmutable
from progress import Progress
from repo_logging import RepoLogger
logger = RepoLogger(__file__)
class ExecuteOneResult(NamedTuple):
project_idx: int
error: Exception
class StartError(RepoExitError):
"""Exit error for failed start command."""
class Start(Command):
COMMON = True
helpSummary = "Start a new branch for development"
helpUsage = """
%prog <newbranchname> [--all | <project>...]
"""
helpDescription = """
'%prog' begins a new branch of development, starting from the
revision specified in the manifest.
"""
PARALLEL_JOBS = DEFAULT_LOCAL_JOBS
def _Options(self, p):
p.add_option(
"--all",
dest="all",
action="store_true",
help="begin branch in all projects",
)
p.add_option(
"-r",
"--rev",
"--revision",
dest="revision",
help="point branch at this revision instead of upstream",
)
p.add_option(
"--head",
"--HEAD",
dest="revision",
action="store_const",
const="HEAD",
help="abbreviation for --rev HEAD",
)
def ValidateOptions(self, opt, args):
if not args:
self.Usage()
nb = args[0]
if not git.check_ref_format("heads/%s" % nb):
self.OptionParser.error("'%s' is not a valid name" % nb)
@classmethod
def _ExecuteOne(cls, revision, nb, default_revisionExpr, project_idx):
"""Start one project."""
# If the current revision is immutable, such as a SHA1, a tag or
# a change, then we can't push back to it. Substitute with
# dest_branch, if defined; or with manifest default revision instead.
branch_merge = ""
error = None
project = cls.get_parallel_context()["projects"][project_idx]
if IsImmutable(project.revisionExpr):
if project.dest_branch:
branch_merge = project.dest_branch
else:
branch_merge = default_revisionExpr
try:
project.StartBranch(
nb, branch_merge=branch_merge, revision=revision
)
except Exception as e:
logger.error("error: unable to checkout %s: %s", project.name, e)
error = e
return ExecuteOneResult(project_idx, error)
def Execute(self, opt, args):
nb = args[0]
err_projects = []
err = []
projects = []
if not opt.all:
projects = args[1:]
if len(projects) < 1:
projects = ["."] # start it in the local project by default
all_projects = self.GetProjects(
projects,
all_manifests=not opt.this_manifest_only,
)
def _ProcessResults(_pool, pm, results):
for result in results:
if result.error:
project = all_projects[result.project_idx]
err_projects.append(project)
err.append(result.error)
pm.update(msg="")
with self.ParallelContext():
self.get_parallel_context()["projects"] = all_projects
self.ExecuteInParallel(
opt.jobs,
functools.partial(
self._ExecuteOne,
opt.revision,
nb,
self.manifest.default.revisionExpr,
),
range(len(all_projects)),
callback=_ProcessResults,
output=Progress(
f"Starting {nb}", len(all_projects), quiet=opt.quiet
),
chunksize=1,
)
if err_projects:
for p in err_projects:
logger.error(
"error: %s/: cannot start %s",
p.RelPath(local=opt.this_manifest_only),
nb,
)
msg_fmt = "cannot start %d project(s)"
self.git_event_log.ErrorEvent(
msg_fmt % (len(err_projects)), msg_fmt
)
raise StartError(aggregate_errors=err)