Apache NuttX is a mature, real-time embedded operating system (RTOS) https://nuttx.apache.org/
Find a file
raiden00pl 753d2a3466
Some checks failed
MemBrowse Memory Report / changes-filter (push) Waiting to run
MemBrowse Memory Report / load-targets (push) Waiting to run
MemBrowse Memory Report / identical (push) Blocked by required conditions
MemBrowse Memory Report / analyze (push) Blocked by required conditions
Build Documentation / build-html (push) Has been cancelled
drivers/serial: fetch uart_writev data from the iovec segment
Since 00010089b8 uart_writev() takes the data one byte at a time with
uio_copyto() plus uio_advance().  Both of them walk the iovec list and
redo the byte counters for every single byte, so most of the work is
bookkeeping rather than copying.  On slow cores this is what limits how
fast the TX buffer can be filled.

Take a pointer to the current iovec segment and read the bytes straight
from it, and move the uio forward once per segment instead of once per
byte.  nseg counts only the bytes that really went into the buffer: it
is increased at the end of a loop pass, and that step is skipped when
uart_putxmitchar() fails.

Measured on nRF52840 (Cortex-M4, 64 MHz), 8 MiB write() to a CDC/ACM
port: 223 KB/s to 481 KB/s.

Signed-off-by: raiden00pl <raiden00@railab.me>
Assisted-by: Claude Code
2026-08-09 03:23:28 +08:00
.github build(deps): bump docker/login-action from 4.5.1 to 4.6.0 2026-08-05 12:38:32 +02:00
arch arch/mips/jz4780: Add hardware Random Number Generator (RNG) support 2026-08-08 15:03:44 -03:00
audio audio: limit the buffer count guard to shared ring requests 2026-08-05 07:58:53 +02:00
binfmt !arch/arm: Use r9 as the PIC base register. 2026-08-06 01:38:23 +08:00
boards boards/nrf53/thingy53: configure XOSC32MCAP 2026-08-08 14:43:09 -03:00
cmake cmake: fix installed application binaries to match Application.mk 2026-08-06 02:39:03 +08:00
crypto tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
Documentation Documentation: add devfreq framework documentation 2026-08-08 15:23:54 -03:00
drivers drivers/serial: fetch uart_writev data from the iovec segment 2026-08-09 03:23:28 +08:00
dummy build: add initial cmake build system 2023-07-08 13:50:48 +08:00
fs fs/fat: Restore the no-short-name marker when the name will not shorten. 2026-08-08 10:05:43 +02:00
graphics tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
include drivers/devfreq: use hardware frequency instead of cached value in driver_target 2026-08-08 15:23:54 -03:00
libs libs/libc/netdb: Size an answer header by its header, not by its union. 2026-08-08 15:02:15 -03:00
mm mm/ubsan: fix signed inline value decoding 2026-07-30 12:52:17 +02:00
net net/igmp: fix checksum validation that always dropped valid IGMP packets 2026-08-07 16:36:42 +08:00
openamp tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
pass1 tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
sched sched/signal: Unblock sigtimedwait through kernel memory. 2026-08-08 14:59:21 -03:00
syscall syscall: add missing memory locking and clock_getres entries 2026-08-08 18:19:27 +08:00
tools !arch/arm: Use r9 as the PIC base register. 2026-08-06 01:38:23 +08:00
video tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
wireless tools: fix stale archive members surviving a Kconfig-driven CSRCS change 2026-07-28 21:26:03 -03:00
.asf.yaml github: master branch protection tune. 2025-05-07 18:37:13 -05:00
.codespell-ignore-lines arch/arm: Reserve r10 via ARCHCFLAGS and hoist the PIC module flags. 2026-07-24 23:09:08 +08:00
.codespellrc arch/arm/rp23xx: Add hardware TRNG driver for /dev/random. 2026-07-25 15:06:56 +08:00
.editorconfig .editorconfig: fix character encoding property specification 2025-11-28 19:12:13 +08:00
.gitignore git: Specify multiple build directories in .gitignore. 2026-05-20 03:06:58 +08:00
.gitmessage docs/contributing: Add a commit message template 2025-06-03 17:33:24 +08:00
.pre-commit-config.yaml pre-commit: enable codespell checks 2025-05-05 12:34:39 +08:00
.yamllint feat: add a GitHub action to lint the YAML files 2020-12-15 09:52:04 -06:00
AUTHORS AUTHORS: add Eren Terzioglu 2026-05-20 15:17:00 +08:00
CMakeLists.txt cmake: Do not link an executable to detect the compiler. 2026-07-25 22:52:39 +08:00
CONTRIBUTING.md contributing: Add requirement for 'Assisted-by' commit field 2026-07-12 09:42:28 +08:00
INVIOLABLES.md
Kconfig sched/misc/assert: Add CONFIG_SCHED_DUMP_TASKS and CONFIG_SCHED_DUMP_STACK 2026-06-09 08:04:54 -04:00
LICENSE libs/libdsp: Add Matrix operations 2026-07-11 14:55:59 -03:00
Makefile !boards: enforce secure ROMFS passwd and TEA key setup 2026-07-09 22:41:11 +08:00
NOTICE Remove the double blank line from source files 2022-02-20 20:10:14 +01:00
README.md ci/testing: Add MemBrowse Integration 2026-06-18 12:07:41 -03:00
ReleaseNotes Documentation: move ReleaseNotes 2023-09-26 20:41:00 +08:00

POSIX Badge License Issues Tracking Badge Contributors GitHub Build Badge Documentation Badge MemBrowse

Apache NuttX is a real-time operating system (RTOS) with an emphasis on standards compliance and small footprint. Scalable from 8-bit to 64-bit microcontroller environments, the primary governing standards in NuttX are POSIX and ANSI standards. Additional standard APIs from Unix and other common RTOSs (such as VxWorks) are adopted for functionality not available under these standards, or for functionality that is not appropriate for deeply-embedded environments (such as fork()).

For brevity, many parts of the documentation will refer to Apache NuttX as simply NuttX.

Getting Started

First time on NuttX? Read the Getting Started guide! If you don't have a board available, NuttX has its own simulator that you can run on terminal.

Documentation

You can find the current NuttX documentation on the Documentation Page.

Alternatively, you can build the documentation yourself by following the Documentation Build Instructions.

The old NuttX documentation is still available in the Apache wiki.

Supported Boards

NuttX supports a wide variety of platforms. See the full list on the Supported Platforms page.

Contributing

If you wish to contribute to the NuttX project, read the Contributing guidelines for information on Git usage, coding standard, workflow and the NuttX principles.

License

The code in this repository is under either the Apache 2 license, or a license compatible with the Apache 2 license. See the License Page for more information.