Fix increase in latency with small messages from websocket compressio…

…n changes (#7797)

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## What do these changes do?

Changes the threshold that is required to compress in the executor for
websocket messages to 5KiB

#7223 changed the websocket
implementation to compress messages > 1KiB in the executor. The
threshold was a bit low which caused an increase in latency compressing
messages as the overhead to use the executor can exceed the cost to
compress tiny messages. When testing 3.9.0 with Home Assistant, we saw a
3 order of magnitude increase in executor usage which resulted in an
overall increase in cpu time since all the tiny messages were being
compressed in the executor.

I could not find the motivation for choosing 1KiB in the original PR

## Are there changes in behavior for the user?

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## Related issue number

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change? -->

## Checklist

- [x] I think the code is well written
- [ ] Unit tests for the changes exist
- [ ] Documentation reflects the changes
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  * name it `<issue_id>.<type>` for example (588.bugfix)
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(cherry picked from commit 27c308b)

CHANGES/7797.bugfix

@@ -0,0 +1 @@
+Fix increase in latency with small messages from websocket compression changes

aiohttp/http_websocket.py

@@ -59,6 +59,15 @@ class WSCloseCode(IntEnum):
 
 ALLOWED_CLOSE_CODES: Final[Set[int]] = {int(i) for i in WSCloseCode}
 
+# For websockets, keeping latency low is extremely important as implementations
+# generally expect to be able to send and receive messages quickly. We use a
+# larger chunk size than the default to reduce the number of executor calls
+# since the executor is a significant source of latency and overhead when
+# the chunks are small. A size of 5KiB was chosen because it is also the
+# same value python-zlib-ng choose to use as the threshold to release the GIL.
+
+WEBSOCKET_MAX_SYNC_CHUNK_SIZE = 5 * 1024
+
 
 class WSMsgType(IntEnum):
  # websocket spec types
@@ -626,11 +635,17 @@ async def _send_frame(
  if (compress or self.compress) and opcode < 8:
  if compress:
  # Do not set self._compress if compressing is for this frame
- compressobj = ZLibCompressor(level=zlib.Z_BEST_SPEED, wbits=-compress)
+ compressobj = ZLibCompressor(
+ level=zlib.Z_BEST_SPEED,
+ wbits=-compress,
+ max_sync_chunk_size=WEBSOCKET_MAX_SYNC_CHUNK_SIZE,
+ )
  else: # self.compress
  if not self._compressobj:
  self._compressobj = ZLibCompressor(
- level=zlib.Z_BEST_SPEED, wbits=-self.compress
+ level=zlib.Z_BEST_SPEED,
+ wbits=-self.compress,
+ max_sync_chunk_size=WEBSOCKET_MAX_SYNC_CHUNK_SIZE,
  )
  compressobj = self._compressobj