Mike O'Driscoll dfdf61c383 control/controlclient: cache sortedPeers result across calls
sortedPeers() copies the entire peers map into a slice and sorts it on
every call. With large peer sets this is expensive — at 50k peers,
each call costs ~9ms and 402KB for the MapValues copy and sort.

Cache the sorted result in sortedPeersCache, protected by peersMu.
The cache is invalidated (set to nil) at the start of
updatePeersStateFromResponse, which is the only writer of the peers
map. sortedPeers uses a read-lock fast path with double-checked
locking on upgrade to write lock.

At 50,000 peers:
- Cache hit (repeated calls): 17.7ns, 0 allocs (was 9.2ms, 402KB)
- After peer change: 9.2ms (unchanged — must re-sort)

Fixes tailscale/corp#40144

Signed-off-by: Mike O'Driscoll <mikeo@tailscale.com>
2026-04-13 19:19:07 +00:00
2026-04-07 15:05:02 -07:00
2026-04-07 11:00:04 -07:00
2026-03-27 08:41:33 +00:00
2026-01-27 16:15:17 -08:00

Tailscale

https://tailscale.com

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:

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 1.26. (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:

WireGuard is a registered trademark of Jason A. Donenfeld.

Description
The easiest, most secure way to use WireGuard and 2FA.
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