Tailscale is making its VPN faster by fixing how it handles tiny packets
Making Tailscale Faster
Tailscale is rolling out performance upgrades that cut memory overhead for small packets, add multi-queue processing for subnet routers and app connectors, and use Linux's writev to reduce copies. Netmap caching lets devices connect faster when the control plane is slow or unreachable. The changes are expected in client v1.104 and later releases.
Bad network conditions—that’s really the space where people can get a lot of utility out of netmap caching.
- apenwarr
(Tailscale cofounder) I see a few comments here that using kernel wireguard would make it faster; it’s not really that simple. In fact, for a while (and we wrote a blog post about it), our optimizations made wireguard-go faster than kernel wireguard because it was better optimized. They adopted some of those improvements and now we’re on to the next order of magnitude together.
For really high bandwidth cases, things like DPDK are the long term best choice and are primarily userspace, for good reasons. Kernel mode is not the pure benefit it once was (if it ever was).
Separately, wireguard itself has a problem that the crypto suite it uses is not supported by hardware accelerators. So if we want to get into the hundreds of gigabits range, we will possibly need to switch packet formats entirely. (But, wireguard also needs to update to support post-quantum so maybe they’ll fix both problems at the same time and we can join in.)
- iscoelho
In my opinion, this is Tailscale's largest issue.
It is slow. It cannot achieve speeds of greater than 1Gbps on clients systems (Windows & Mac), where you'd normally see it being used. On Linux, it struggles to achieve 10Gbps even when using a synthetic large packet benchmark [1]. With an IMIX benchmark, it would not be competitive whatsoever.
This problem is fixable. WireGuard achieves higher performance (Kernel vs Userspace implementation) and IPsec implementations can achieve 100Gbps/400Gbps (DPDK/XDP). Zero-copy networking.
From this blog post, I can say Tailscale still seems to not have the appetite for that, which is a shame.
- fitblipper
I used to LOVE tailscale. Then I put wireguard on my home network exposed to the internet with a dynamic DNS provider and it immediately became irrelevant. Not only is raw wireguard more stable (I don't have to fight the DNS issues on my mobile phones) it feels faster and is amazingly simple to set up.
- CharlesW
I wonder if the post's focus on Linux/Android is just because that's where they started, or because they're leveraging techniques that are only possible on Linux/Android?
- ykurtov
In our use case latency went parabolic at 250 sessions pumping just 60 mb/s through a tunnel.