Brad Fitzpatrick
51682d245b
Each client connection ran two goroutines for its lifetime: the reader in sclient.run and a sendLoop blocked in a select over its send queues, pong, peer gone, mesh update, and keepalive channels. Almost all clients are idle at any moment, so the second goroutine mostly pinned memory: a 4 KiB stack, a g struct, a sudog per select case, three channels, and a context and errgroup. At 100k idle connections that was about 8 KB of a client's 22 KB RSS. Instead, start up the sendLoop only as needed, letting the goroutine go away otherwise, like Go 1.28-dev's http2 code (golang/go@5c51011e82) with similar parking to https://go.dev/cl/834084 but DERP's producers are all non-blocking, so a kick bit replaces that http2 code's send count. Measured with 100k idle TLS connections, server RSS per client went from 22.3 KB to 14.5 KB (22.9 KB to 15.3 KB after each connection had carried a packet), goroutines dropped from 2 to 1, and with no change in BenchmarkSendRecv throughput or allocations and no change in the time to do 100k serial round trips, each of which parks and wakes the writer. (it's super cheap to start goroutines) Updates #21064 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com> Change-Id: I7c3e9a51d4b8f2607a1e5c3d9f8b2a4e6c0d1f3b
Tailscale
Private WireGuard® networks made easy
Overview
This repository contains the majority of Tailscale's open source code.
Notably, it includes the tailscaled daemon and
the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows,
macOS, and to varying degrees
on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's
code, but this repo doesn't contain the mobile GUI code.
Other Tailscale repos of note:
- the Android app is at https://github.com/tailscale/tailscale-android
- the Synology package is at https://github.com/tailscale/tailscale-synology
- the QNAP package is at https://github.com/tailscale/tailscale-qpkg
- the Chocolatey packaging is at https://github.com/tailscale/tailscale-chocolatey
For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.
Using
We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.
Other clients
The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.
Building
We always require the latest Go release, currently Go 1.27. (While we build releases with our Go fork, its use is not required.)
go install tailscale.com/cmd/tailscale{,d}
If you're packaging Tailscale for distribution, use build_dist.sh
instead, to burn commit IDs and version info into the binaries:
./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled
If your distro has conventions that preclude the use of
build_dist.sh, please do the equivalent of what it does in your
distro's way, so that bug reports contain useful version information.
Bugs
Please file any issues about this code or the hosted service on the issue tracker.
Contributing
PRs welcome! But please file bugs. Commit messages should reference bugs.
We require Developer Certificate of
Origin
Signed-off-by lines in commits.
See commit-messages.md (or skim git log) for our commit message style.
About Us
Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:
- https://github.com/tailscale/tailscale/graphs/contributors
- https://github.com/tailscale/tailscale-android/graphs/contributors
Legal
WireGuard is a registered trademark of Jason A. Donenfeld.