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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>
This commit is contained in:
Kuang-che Wu 2024-10-22 21:04:41 +08:00 committed by LUCI
parent 39ffd9977e
commit 8da4861b38
11 changed files with 230 additions and 174 deletions

View file

@ -20,7 +20,6 @@ from command import DEFAULT_LOCAL_JOBS
from error import GitError
from error import RepoExitError
from progress import Progress
from project import Project
from repo_logging import RepoLogger
@ -30,7 +29,7 @@ logger = RepoLogger(__file__)
class CheckoutBranchResult(NamedTuple):
# Whether the Project is on the branch (i.e. branch exists and no errors)
result: bool
project: Project
project_idx: int
error: Exception
@ -62,15 +61,17 @@ The command is equivalent to:
if not args:
self.Usage()
def _ExecuteOne(self, nb, project):
@classmethod
def _ExecuteOne(cls, nb, project_idx):
"""Checkout one project."""
error = None
result = None
project = cls.get_parallel_context()["projects"][project_idx]
try:
result = project.CheckoutBranch(nb)
except GitError as e:
error = e
return CheckoutBranchResult(result, project, error)
return CheckoutBranchResult(result, project_idx, error)
def Execute(self, opt, args):
nb = args[0]
@ -83,22 +84,25 @@ The command is equivalent to:
def _ProcessResults(_pool, pm, results):
for result in results:
project = all_projects[result.project_idx]
if result.error is not None:
err.append(result.error)
err_projects.append(result.project)
err_projects.append(project)
elif result.result:
success.append(result.project)
success.append(project)
pm.update(msg="")
self.ExecuteInParallel(
opt.jobs,
functools.partial(self._ExecuteOne, nb),
all_projects,
callback=_ProcessResults,
output=Progress(
f"Checkout {nb}", len(all_projects), quiet=opt.quiet
),
)
with self.ParallelContext():
self.get_parallel_context()["projects"] = all_projects
self.ExecuteInParallel(
opt.jobs,
functools.partial(self._ExecuteOne, nb),
range(len(all_projects)),
callback=_ProcessResults,
output=Progress(
f"Checkout {nb}", len(all_projects), quiet=opt.quiet
),
)
if err_projects:
for p in err_projects: