5ecd14a31c
691eaf8873Pass MSG_MORE flag when sending non-final network messages (Matt Whitlock) Pull request description: **N.B.:** This is my second attempt at introducing this optimization. #12519 (2018) was closed in deference to switching to doing gathering socket writes using `sendmsg(2)`, which I agree would have superior performance due to fewer syscalls, but that work was apparently abandoned in late 2018. Ever since, Bitcoin Core has continued writing tons of runt packets to the wire. Can we proceed with my halfway solution for now? ---- Since Nagle's algorithm is disabled, each and every call to `send(2)` can potentially generate a separate TCP segment on the wire. This is especially inefficient when sending the tiny header preceding each message payload. Linux implements a `MSG_MORE` flag that tells the kernel not to push the passed data immediately to the connected peer but rather to collect it in the socket's internal transmit buffer where it can be combined with data from successive calls to `send(2)`. Where available, specify this flag when calling `send(2)` in `CConnman::SocketSendData(CNode &)` if the data buffer being sent is not the last one in `node.vSendMsg`. ACKs for top commit: sipa: ACK691eaf8873vasild: ACK691eaf8873Tree-SHA512: 9a7f46bc12edbf78d488f05d1c46760110a24c95af74b627d2604fcd198fa3f511c5956bac36d0034e88c632d432f7d394147e667a11b027af0a30f70a546d70
Bitcoin Core integration/staging tree
For an immediately usable, binary version of the Bitcoin Core software, see https://bitcoincore.org/en/download/.
What is Bitcoin Core?
Bitcoin Core connects to the Bitcoin peer-to-peer network to download and fully validate blocks and transactions. It also includes a wallet and graphical user interface, which can be optionally built.
Further information about Bitcoin Core is available in the doc folder.
License
Bitcoin Core is released under the terms of the MIT license. See COPYING for more information or see https://opensource.org/licenses/MIT.
Development Process
The master branch is regularly built (see doc/build-*.md for instructions) and tested, but it is not guaranteed to be
completely stable. Tags are created
regularly from release branches to indicate new official, stable release versions of Bitcoin Core.
The https://github.com/bitcoin-core/gui repository is used exclusively for the development of the GUI. Its master branch is identical in all monotree repositories. Release branches and tags do not exist, so please do not fork that repository unless it is for development reasons.
The contribution workflow is described in CONTRIBUTING.md and useful hints for developers can be found in doc/developer-notes.md.
Testing
Testing and code review is the bottleneck for development; we get more pull requests than we can review and test on short notice. Please be patient and help out by testing other people's pull requests, and remember this is a security-critical project where any mistake might cost people lots of money.
Automated Testing
Developers are strongly encouraged to write unit tests for new code, and to
submit new unit tests for old code. Unit tests can be compiled and run
(assuming they weren't disabled in configure) with: make check. Further details on running
and extending unit tests can be found in /src/test/README.md.
There are also regression and integration tests, written
in Python.
These tests can be run (if the test dependencies are installed) with: test/functional/test_runner.py
The CI (Continuous Integration) systems make sure that every pull request is built for Windows, Linux, and macOS, and that unit/sanity tests are run automatically.
Manual Quality Assurance (QA) Testing
Changes should be tested by somebody other than the developer who wrote the code. This is especially important for large or high-risk changes. It is useful to add a test plan to the pull request description if testing the changes is not straightforward.
Translations
Changes to translations as well as new translations can be submitted to Bitcoin Core's Transifex page.
Translations are periodically pulled from Transifex and merged into the git repository. See the translation process for details on how this works.
Important: We do not accept translation changes as GitHub pull requests because the next pull from Transifex would automatically overwrite them again.