valence/performance_tests/README.md
Ryan Johnson f4714cf255
Redesign packet processing and improve Client update procedure. (#146)
Closes #82
Closes #43
Closes #64

# Changes and Improvements
- Packet encoding/decoding happens within `Client` instead of being sent
over a channel first. This is better for performance and lays the
groundwork for #83.
- Reduce the amount of copying necessary by leveraging the `bytes` crate
and recent changes to `EncodePacket`. Performance is noticeably improved
with maximum players in the `rust-mc-bot` test going from 750 to 1050.
- Packet encoding/decoding code is decoupled from IO. This is easier to
understand and more suitable for a future protocol lib.
- Precise control over the number of bytes that are buffered for
sending/receiving. This is important for limiting maximum memory usage
correctly.
- "packet controllers" are introduced, which are convenient structures
for managing packet IO before and during the play state.
- `byte_channel` module is created to help implement the
`PlayPacketController`. This is essentially a channel of bytes
implemented with an `Arc<Mutex<BytesMut>>`.
- Error handling in the update procedure for clients was improved using
`anyhow::Result<()>` to exit as early as possible. The `client` module
is a bit cleaner as a result.
- The `LoginPlay` packet is always sent before all other play packets.
We no longer have to worry about the behavior of packets sent before
that packet. Most packet deferring performed currently can be
eliminated.
- The packet_inspector was rewritten in response to the above changes.
- Timeouts on IO operations behave better.

# Known Issues
- The packet_inspector now re-encodes packets rather than just decoding
them. This will cause problems when trying to use it with the vanilla
server because there are missing clientbound packets and other issues.
This will be fixed when the protocol module is moved to a separate
crate.
2022-11-01 03:11:51 -07:00

846 B

Performance Tests

Run the server

cargo r -r -p players

In a separate terminal, start rust-mc-bot. This command should connect 1000 clients to the server.

# In the rust-mc-bot directory
cargo r -r -- 127.0.0.1:25565 1000

If the delta time is consistently >50ms, the server is running behind schedule.

Note:

Flamegraph

To start capturing a flamegraph, run the server like this:

# You can also try setting the `CARGO_PROFILE_RELEASE_DEBUG` environment variable to `true`.
cargo flamegraph -p players

Run rust-mc-bot as above, and then stop the server after a few seconds. Flamegraph will generate a flamegraph.svg in the current directory. You can then open that file in your internet browser of choice.