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

@ -713,16 +713,17 @@ Gerrit Code Review: https://www.gerritcodereview.com/
merge_branch = p.stdout.strip()
return merge_branch
@staticmethod
def _GatherOne(opt, project):
@classmethod
def _GatherOne(cls, opt, project_idx):
"""Figure out the upload status for |project|."""
project = cls.get_parallel_context()["projects"][project_idx]
if opt.current_branch:
cbr = project.CurrentBranch
up_branch = project.GetUploadableBranch(cbr)
avail = [up_branch] if up_branch else None
else:
avail = project.GetUploadableBranches(opt.branch)
return (project, avail)
return (project_idx, avail)
def Execute(self, opt, args):
projects = self.GetProjects(
@ -732,8 +733,9 @@ Gerrit Code Review: https://www.gerritcodereview.com/
def _ProcessResults(_pool, _out, results):
pending = []
for result in results:
project, avail = result
project_idx, avail = result
if avail is None:
project = projects[project_idx]
logger.error(
'repo: error: %s: Unable to upload branch "%s". '
"You might be able to fix the branch by running:\n"
@ -746,12 +748,14 @@ Gerrit Code Review: https://www.gerritcodereview.com/
pending.append(result)
return pending
pending = self.ExecuteInParallel(
opt.jobs,
functools.partial(self._GatherOne, opt),
projects,
callback=_ProcessResults,
)
with self.ParallelContext():
self.get_parallel_context()["projects"] = projects
pending = self.ExecuteInParallel(
opt.jobs,
functools.partial(self._GatherOne, opt),
range(len(projects)),
callback=_ProcessResults,
)
if not pending:
if opt.branch is None: