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Justin M. Keyes 98053bfecf perf(input): drop buffheader_T #41353
Problem:
`buffheader_T` is a linked list (Vim's favorite data structure) with
complex bookkeeping, optimized for ancient hardware:

1. Memory topology: On old platforms (Amiga 512KB without MMU, MS-DOS
   64KB segments), large contiguous allocations were hazardous (no VM).
2. Never-move appends: `add_buff()` fills spare space or links a new
   block.
3. OOM "recovery": a failed block allocation only loses one append.

To avoid OOM, it prefers to allocate small, linked chunks, instead of
resizing one continguous slice. Each stuff/drain cycle costs
a malloc+free.

Solution:
Replace Vim's favorite data structure with Nvim's favorite data structure.

Nvim doesn't have granular handling of OOM (`xmalloc`), and hardware has
changed: caches favor contiguous memory, allocators handle
fragmentation. And these buffers are ~kb scale, so OOM is irrelevant on
any system that can run Nvim.

- Use a flat `StringBuilder` + `read`/`insert` offsets.
- Keeps capacity (does not shrink) until `free_buff`.
- "Steady state" allocates nothing: 1 fewer malloc+free per dot-repeat.
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2026-08-17 07:55:47 -04:00
2025-12-30 01:44:52 -05:00
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2026-03-11 18:00:18 +01:00
2026-04-16 10:48:11 -04:00

Neovim

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Neovim is a project that seeks to aggressively refactor Vim in order to:

See the Introduction wiki page and Roadmap for more information.

Features

See :help nvim-features for the full list, and :help news for noteworthy changes in the latest version!

Install from package

Pre-built packages for Windows, macOS, and Linux are found on the Releases page.

Managed packages are in Homebrew, Debian, Ubuntu, Fedora, Arch Linux, Void Linux, Gentoo, and more!

Install from source

See BUILD.md and supported platforms for details.

The build is CMake-based, but a Makefile is provided as a convenience. After installing the dependencies, run the following command.

make CMAKE_BUILD_TYPE=RelWithDebInfo
sudo make install

To install to a non-default location:

make CMAKE_BUILD_TYPE=RelWithDebInfo CMAKE_INSTALL_PREFIX=/full/path/
make install

CMake hints for inspecting the build:

  • cmake --build build --target help lists all build targets.
  • build/CMakeCache.txt (or cmake -LAH build/) contains the resolved values of all CMake variables.
  • build/compile_commands.json shows the full compiler invocations for each translation unit.

Transitioning from Vim

See :help nvim-from-vim for instructions.

Project layout

├─ cmake/           CMake utils
├─ cmake.config/    CMake defines
├─ cmake.deps/      subproject to fetch and build dependencies (optional)
├─ runtime/         plugins and docs
├─ src/nvim/        application source code (see src/nvim/README.md)
│  ├─ api/          API subsystem
│  ├─ eval/         Vimscript subsystem
│  ├─ event/        event-loop subsystem
│  ├─ generators/   code generation (pre-compilation)
│  ├─ lib/          generic data structures
│  ├─ lua/          Lua subsystem
│  ├─ msgpack_rpc/  RPC subsystem
│  ├─ os/           low-level platform code
│  └─ tui/          built-in UI
└─ test/            tests (see test/README.md)

License

Neovim contributions since b17d96 are licensed under the Apache 2.0 license, except for contributions copied from Vim (identified by the vim-patch token). See LICENSE.txt for details.

Description
Vim-fork focused on extensibility and usability
Readme 509 MiB
Languages
Vim Script 39.7%
Lua 32.6%
C 26.7%
CMake 0.4%
Zig 0.2%
Other 0.1%