* Introduction of Happy Eyeballs Version 2 (RFC8305) in TCPSocket.new
This is an implementation of Happy Eyeballs version 2 (RFC 8305) in `TCPSocket.new`.
See https://github.com/ruby/ruby/pull/11653
1. Background
Prior to this implementation, I implemented Happy Eyeballs Version 2 (HEv2) for `Socket.tcp` in https://github.com/ruby/ruby/pull/9374.
HEv2 is an algorithm defined in [RFC 8305](https://datatracker.ietf.org/doc/html/rfc8305), aimed at improving network connectivity.
For more details on the specific cases that HEv2 helps, please refer to https://bugs.ruby-lang.org/issues/20108.
2. Proposal & Outcome
This proposal implements the same HEv2 algorithm in `TCPSocket.new`.
Since `TCPSocket.new` is used more widely than `Socket.tcp`, this change is expected to broaden the impact of HEv2's benefits.
Like `Socket.tcp`, I have also added `fast_fallback` keyword argument to `TCPSocket.new`.
This option is set to true by default, enabling the HEv2 functionality.
However, users can explicitly set it to false to disable HEv2 and use the previous behavior of `TCPSocket.new`.
It should be noted that HEv2 is enabled only in environments where pthreads are available.
This specification follows the approach taken in https://bugs.ruby-lang.org/issues/19965 , where name resolution can be interrupted.
(In environments where pthreads are not available, the `fast_fallback` option is ignored.)
3. Performance
Below is the benchmark of 100 requests to `www.ruby-lang.org` with the fast_fallback option set to true and false, respectively.
While there is a slight performance degradation when HEv2 is enabled, the degradation is smaller compared to that seen in `Socket.tcp`.
```
~/s/build ❯❯❯ ../install/bin/ruby ../ruby/test.rb
Rehearsal --------------------------------------------------------
fast_fallback: true 0.017588 0.097045 0.114633 ( 1.460664)
fast_fallback: false 0.014033 0.078984 0.093017 ( 1.413951)
----------------------------------------------- total: 0.207650sec
user system total real
fast_fallback: true 0.020891 0.124054 0.144945 ( 1.473816)
fast_fallback: false 0.018392 0.110852 0.129244 ( 1.466014)
```
* Update debug prints
Co-authored-by: Nobuyoshi Nakada <nobu.nakada@gmail.com>
* Remove debug prints
* misc
* Disable HEv2 in Win
* Raise resolution error with hostname resolution
* Fix to handle errors
* Remove warnings
* Errors that do not need to be handled
* misc
* Improve doc
* Fix bug on cancellation
* Avoid EAI_ADDRFAMILY for resolving IPv6
* Follow upstream
* misc
* Refactor connection_attempt_fds management
- Introduced allocate_connection_attempt_fds and reallocate_connection_attempt_fds for improved memory allocation of connection_attempt_fds
- Added remove_connection_attempt_fd to resize connection_attempt_fds dynamically.
- Simplified the in_progress_fds function to only check the size of connection_attempt_fds.
* Rename do_pthread_create to raddrinfo_pthread_create to avoid conflicting
---------
Co-authored-by: Nobuyoshi Nakada <nobu.nakada@gmail.com>