⚡️ Speed up method MarimoComm._publish_msg by 41%

[codeflash-ai]

📄 41% (0.41x) speedup for MarimoComm._publish_msg in marimo/_plugins/ui/_impl/comm.py

⏱️ Runtime : 121 microseconds → 86.0 microseconds (best of 77 runs)

📝 Explanation and details

The optimized code achieves a 41% speedup through two key optimizations:

1. Import Hoisting (Major Impact)
The most significant optimization moves from marimo._messaging.ops import SendUIElementMessage from inside the flush() method to module scope. The line profiler shows this import was taking 17.5% of flush() runtime (186,800ns out of 1,069,800ns total). By hoisting it to module scope, this cost is eliminated from the hot path, providing substantial savings when flush() is called frequently.

2. Conditional Logic Consolidation (Minor Impact)
The three separate if statements checking msg_type equality are consolidated into a single set membership check: if msg_type in {COMM_OPEN_NAME, COMM_MESSAGE_NAME, COMM_CLOSE_NAME}. This reduces the number of string comparisons from up to 3 down to 1, and eliminates redundant code paths that were executing identical logic.

Performance Analysis:

• The test results show consistent 26-43% improvements across different message types and volumes
• The optimization is particularly effective for high-frequency scenarios (the 50-message test shows 43.3% improvement)
• Both basic single-message calls and bulk operations benefit significantly

Impact on Workloads:
This optimization is especially valuable for UI-intensive applications where widgets frequently publish messages (open, update, close operations). Since MarimoComm appears to be part of marimo's UI plugin system, these methods likely execute in hot paths during interactive notebook usage, making the performance gains meaningful for user experience.

The optimizations maintain complete behavioral equivalence while eliminating redundant work, making this a safe and effective performance improvement.

✅ Correctness verification report:

Test	Status
⚙️ Existing Unit Tests	🔘 None Found
🌀 Generated Regression Tests	✅ 57 Passed
⏪ Replay Tests	🔘 None Found
🔎 Concolic Coverage Tests	🔘 None Found
📊 Tests Coverage	100.0%

🌀 Generated Regression Tests and Runtime

import pytest
from marimo._plugins.ui._impl.comm import MarimoComm

Minimal stubs for dependencies needed by MarimoComm._publish_msg

class DummyLogger:
def init(self):
self.warnings = []
def warning(self, *args):
self.warnings.append(args)

Simulate the MessageBufferData used in MarimoComm

class MessageBufferData:
def init(self, data, metadata, buffers, model_id):
self.data = data
self.metadata = metadata
self.buffers = buffers
self.model_id = model_id

Dummy SendUIElementMessage for flush

class DummySendUIElementMessage:
def init(self, ui_element, model_id, message, buffers):
self.ui_element = ui_element
self.model_id = model_id
self.message = message
self.buffers = buffers
DummySendUIElementMessage.sent.append(self)
def broadcast(self):
DummySendUIElementMessage.broadcasted.append(self)

DummySendUIElementMessage.sent = []
DummySendUIElementMessage.broadcasted = []

Patch marimo_comm flush to use dummy SendUIElementMessage

def dummy_flush(self):
while self._publish_message_buffer:
item = self._publish_message_buffer.pop(0)
DummySendUIElementMessage(
ui_element=self.ui_element_id,
model_id=item.model_id,
message=item.data,
buffers=item.buffers,
).broadcast()

Dummy comm manager for registration

class DummyCommManager:
def init(self):
self.registered = []
self.unregistered = []
def register_comm(self, comm):
self.registered.append(comm)
def unregister_comm(self, comm):
self.unregistered.append(comm)
from marimo._plugins.ui._impl.comm import MarimoComm

@pytest.fixture
def comm():
# Provide a fresh MarimoComm for each test
comm_manager = DummyCommManager()
return MarimoComm(
comm_id="test_model_id",
comm_manager=comm_manager,
target_name="target",
)

1. BASIC TEST CASES

def test_publish_open_message_basic(comm):
"""Test publishing a basic COMM_OPEN message with simple data."""
comm._publish_msg(
comm.COMM_OPEN_NAME,
data={"foo": 1},
metadata={"bar": 2},
buffers=[b"abc"]
)
sent = DummySendUIElementMessage.sent[0]

def test_publish_comm_message_basic(comm):
"""Test publishing a basic COMM_MESSAGE message with no data."""
comm._publish_msg(comm.COMM_MESSAGE_NAME)
sent = DummySendUIElementMessage.sent[0]

def test_publish_close_message_basic(comm):
"""Test publishing a basic COMM_CLOSE message."""
comm._publish_msg(comm.COMM_CLOSE_NAME, data={"baz": 42})
sent = DummySendUIElementMessage.sent[0]

def test_publish_multiple_messages(comm):
"""Test publishing multiple messages in sequence."""
comm._publish_msg(comm.COMM_OPEN_NAME, data={"a": 1})
comm._publish_msg(comm.COMM_MESSAGE_NAME, data={"b": 2})
comm._publish_msg(comm.COMM_CLOSE_NAME, data={"c": 3})

2. EDGE TEST CASES

def test_publish_msg_with_none_values(comm):
"""Test that None data/metadata/buffers are replaced with defaults."""
comm._publish_msg(comm.COMM_OPEN_NAME, data=None, metadata=None, buffers=None)
sent = DummySendUIElementMessage.sent[0]

def test_publish_msg_with_empty_dicts_and_lists(comm):
"""Test that empty dicts/lists are preserved as is."""
comm._publish_msg(comm.COMM_MESSAGE_NAME, data={}, metadata={}, buffers=[])
sent = DummySendUIElementMessage.sent[0]

def test_publish_msg_with_large_buffer(comm):
"""Test that large buffer is handled correctly."""
big_buffer = [b"x" * 1024] * 10 # 10 KB total
comm._publish_msg(comm.COMM_OPEN_NAME, buffers=big_buffer)
sent = DummySendUIElementMessage.sent[0]

def test_publish_msg_with_unusual_types(comm):
"""Test that non-string keys and values in data/metadata are handled."""
class Weird:
def eq(self, other): return True
data = {42: Weird()}
metadata = {None: [1, 2, 3]}
comm._publish_msg(comm.COMM_MESSAGE_NAME, data=data, metadata=metadata)
sent = DummySendUIElementMessage.sent[0]

def test_publish_msg_with_extra_kwargs(comm):
"""Test that extra kwargs are ignored."""
comm._publish_msg(comm.COMM_OPEN_NAME, data={"x": 1}, extra1=123, extra2="abc")
sent = DummySendUIElementMessage.sent[0]

3. LARGE SCALE TEST CASES

def test_publish_msg_many_messages(comm):
"""Test publishing many messages in quick succession."""
for i in range(100):
comm._publish_msg(comm.COMM_MESSAGE_NAME, data={"i": i})

def test_publish_msg_large_data_and_metadata(comm):
"""Test with both large data and metadata."""
data = {str(i): i for i in range(500)}
metadata = {str(i): -i for i in range(500)}
comm._publish_msg(comm.COMM_MESSAGE_NAME, data=data, metadata=metadata)
sent = DummySendUIElementMessage.sent[0]

codeflash_output is used to check that the output of the original code is the same as that of the optimized code.

#------------------------------------------------
from typing import Any, Callable, Optional

imports

import pytest
from marimo._plugins.ui._impl.comm import MarimoComm

--- Minimal stubs and helpers to make the test self-contained ---

class DummyLogger:
def init(self):
self.last_warning = []

def warning(self, *args):
    self.last_warning.append(args)

class DummySendUIElementMessage:
# records all calls for inspection
calls = []
def init(self, ui_element, model_id, message, buffers):
self.ui_element = ui_element
self.model_id = model_id
self.message = message
self.buffers = buffers
DummySendUIElementMessage.calls.append(self)

def broadcast(self):
    # no-op for test
    pass

Patch for marimo_logger and MessageBufferData

LOGGER = DummyLogger()

Constants as in the real code

COMM_MESSAGE_NAME = "marimo_comm_msg"
COMM_OPEN_NAME = "marimo_comm_open"
COMM_CLOSE_NAME = "marimo_comm_close"

--- MarimoComm minimal stub for testing ---

class DummyCommManager:
def register_comm(self, comm): pass
def unregister_comm(self, comm): pass

@pytest.fixture
def comm():
# Provide a fresh MarimoComm for each test
return MarimoComm(
comm_id="test_id",
comm_manager=DummyCommManager(),
target_name="test_target"
)

---------------- BASIC TEST CASES ----------------

def test_publish_msg_multiple_calls(comm):
"""Test multiple sequential publish_msg calls."""
comm._publish_msg(COMM_OPEN_NAME, data={"x": 1}) # 5.58μs -> 4.41μs (26.7% faster)
comm._publish_msg(COMM_MESSAGE_NAME, data={"y": 2}) # 2.86μs -> 2.12μs (34.9% faster)
comm._publish_msg(COMM_CLOSE_NAME, data={"z": 3}) # 2.23μs -> 1.71μs (30.4% faster)

---------------- EDGE TEST CASES ----------------

def test_publish_msg_buffers_mutation(comm):
"""Test that buffers passed in are not mutated by the function."""
buffers = [b"a", b"b"]
comm._publish_msg(COMM_MESSAGE_NAME, buffers=buffers) # 5.53μs -> 4.39μs (26.0% faster)

def test_publish_msg_many_sequential_calls(comm):
"""Test many sequential publish_msg calls."""
for i in range(50):
comm._publish_msg(COMM_MESSAGE_NAME, data={"i": i}) # 105μs -> 73.4μs (43.3% faster)
for idx, call in enumerate(DummySendUIElementMessage.calls):
pass

#------------------------------------------------
*** Begin Not Deterministic Debug ***
Previous iteration: 1
Current SMT expression: comm_id_3len_4 != comm_id_3len_4
Current stack tail:
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/libimpl/builtinslib.py:2785
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/libimpl/builtinslib.py:3510
/home/ubuntu/work/repo/marimo/_plugins/ui/_impl/comm.py:24
/home/ubuntu/work/repo/marimo/_plugins/ui/_impl/comm.py:113
/home/ubuntu/work/repo/marimo/_plugins/ui/_impl/comm.py:104
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/enforce.py:43
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/core.py:498
proxy_arg_self.py:705
Previous stack tail:
proxy_arg_msg_type.py:698
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/core.py:755
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/core.py:1375
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/path_cover.py:130
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:773
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:930
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:969
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:8
Reason: Wrong node type (is ParallelNode, expected WorstResultNode)
*** End Not Deterministic Debug ***
*** Begin Not Deterministic Debug ***
Previous iteration: 68
Current SMT expression: comm_id_3len_4 != comm_id_3len_4
Current stack tail:
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/libimpl/builtinslib.py:2785
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/libimpl/builtinslib.py:3510
/home/ubuntu/work/repo/marimo/_plugins/ui/_impl/comm.py:24
/home/ubuntu/work/repo/marimo/_plugins/ui/_impl/comm.py:113
/home/ubuntu/work/repo/marimo/_plugins/ui/_impl/comm.py:104
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/enforce.py:43
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/core.py:498
proxy_arg_self.py:705
Previous stack tail:
proxy_arg_msg_type.py:698
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/core.py:755
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/core.py:1375
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/path_cover.py:130
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:773
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:930
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:969
/home/ubuntu/work/repo/.venv/lib/python3.10/site-packages/crosshair/main.py:8
Reason: Wrong node type (is ParallelNode, expected WorstResultNode)
*** End Not Deterministic Debug ***
from marimo._plugins.ui._impl.comm import MarimoComm
from marimo._plugins.ui._impl.comm import MarimoCommManager

def test_MarimoComm__publish_msg():
MarimoComm._publish_msg(MarimoComm('', MarimoCommManager(), '', data={'': ''}, metadata=None, buffers=None, =0), 'marimo_comm_close', data={}, metadata=None, buffers=None)

def test_MarimoComm__publish_msg_2():
MarimoComm._publish_msg(MarimoComm('', MarimoCommManager(), '', data={}, metadata=None, buffers=[]), 'marimo_comm_open', data=None, metadata={}, buffers=[b''])

def test_MarimoComm__publish_msg_3():
MarimoComm._publish_msg(MarimoComm('', MarimoCommManager(), '', data=None, metadata={}, buffers=None), 'marimo_comm_msg', data=None, metadata=None, buffers=None)

def test_MarimoComm__publish_msg_4():
MarimoComm._publish_msg(MarimoComm('', MarimoCommManager(), '', data=None, metadata={}, buffers=[], =''), '', data=None, metadata={'': ''}, buffers=None)

To edit these changes git checkout codeflash/optimize-MarimoComm._publish_msg-mhv6d2t5 and push.