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WSL3 Performance is about 5-60% faster than WSL2 depending on the workload

71 points tonymet 2 days ago 38 comments

tonymet 2 days ago | parent

Despite the container support getting most of the attention, I discovered a measurable performance improvement with WSL3 by accident. Luckily I had another machine to upgrade so I ran an AB test comparing WSL 2 to WSL3 .

If you want a real bump in performance, I have a clever trick . Hardware isn’t cheap these days, so we demand the most of our software.

Leonard_of_Q 40 minutes ago | parent

> If you want a real bump in performance, I have a clever trick . Hardware isn’t cheap these days, so we demand the most of our software.

Good trick: get rid of the superfluous Windows layer which stands between that expensive hardware and your target OS. It takes up valuable memory, CPU time and storage space, introduces latency where you don't want it, exfiltrates data to unknown destinations and can decide to "upgrade" itself without warning.

Good tricks need catchy names to succeed so how about NoSL?

armcat 2 hours ago | parent

Great job in benchmarking! I wasn't even aware of the WSLc (WSL3) release. For others, the release info is available here: https://github.com/microsoft/WSL/releases/tag/3.0.1

EDIT: stumbled on the previous HN post here: https://news.ycombinator.com/item?id=49970507

pjmlp 1 hour ago | parent

That is quite relevant, and compose ability is on the way, or for some workloads Aspire would be an alternative I guess.

Unfortunately most companies are too cheap to pay for Docker Desktop, and having Windows containers depend on a third party tool has been a problem in such customers.

Because using Rancher Desktop or Podman isn't also a given, due to similar issues.

Randomno 1 hour ago | parent

Is it accurate to call this WSL3? WSL 2 was released in 2019, but WSL 2.0.0 was released in 2023 https://github.com/microsoft/WSL/releases/tag/2.0.0

cdud3 1 hour ago | parent

And yet it's still factors faster without a whole Windows around it.

pjmlp 1 hour ago | parent

Unfortunately that acquisition option isn't available in most physical stores, where normies buy their computers, even though there isn't a single OEM not running some distro on their data centers.

TZubiri 1 hour ago | parent

everything I use it for executes virtually instantly, 60% slower than virtually instantly is still virtually instantly.

If something is slow on WSL, but not on bare metal linux, it means that the application is slop that only works when MAXING OUT your CPU, it's slop, the app is the slop

pjmlp 1 hour ago | parent

Yeah, I haven't dual booted in decades, it started with Windows 7 and VMWare Workstation for me.

The Year of Desktop Linux is delivered on VMs.

la_fayette 1 hour ago | parent

ok great benchmark! I work with herdr/pi for dev work and need to use a windows machine from my company. WSL currently unfortunately lags so much when typing, not sure why when using herdr... Using powershell, some features are missing, so i can't wait to try WSL3 and hope for improvements.

TZubiri 1 hour ago | parent

... does it lag on the shell or does it lag when you are in some vibecoded "TUI" njs monstrosity? Because if the latter, the issue is probably not cause of wsl...

ricardobeat 1 hour ago | parent

herdr might be the culprit there, it can significantly slow down tui apps with its terminal capture. This happens on mac/linux, WSL will surely make it worse.

la_fayette 1 hour ago | parent

The TUIs alone work fine, so something must be done by herdr to make it slow...

xaduha 1 hour ago | parent

I find that stuff that it offers over a normal Hyper-V VM is stuff that I don't need, leaky abstractions galore.

shevy-java 47 minutes ago | parent

Well, you can use linux-tools on windows too. I kind of compiled most of LFS/BLFS on it, and it works. So it just gives you more options.

binsquare 1 hour ago | parent

Lot of the WSL2 lag is not the VM itself, it's the 9P file sharing and interop.

I found that seems like anything under /mnt/c goes through 9P

usrusr 50 minutes ago | parent

And yet I had results perfectly within the range of "good enough" having an ai harness muck about in a work folder in a docker mount on a 9P mapped drive under permanent observation by an intelliJ instance on the Windows side before some buggy Windows update made it occasionally lock up under `npm i` sized filesystem loads. Crazy how far we've come.

pjmlp 48 minutes ago | parent

There is virtio support now, and to be fair 9P was never an issue for me.

DiabloD3 24 minutes ago | parent

9P is very slow for certain operations (such as, for example, git from either direction).

virtio is not enabled by default because its buggy in certain corner cases, and will be enabled by default when it stops doing that. That said, I do have that enabled, it is certainly faster.

pjmlp 14 minutes ago | parent

Since nowadays I use WSL to run immutable containers, and not really classical Linux Desktop, it isn't something that bothers me.

Agents take more time than building Docker images.

chris_money202 33 minutes ago | parent

You’re not supposed to work out of the /mnt/c. A lot of people make this mistake and then complain that WSL is slow. On the native linux file system WSL is 100x faster for everything

1718627440 1 hour ago | parent

WSL2 is a different product from WSL1, not a different version. Is WSL3 now a different version of WSL2 or another separate product?

pilif 1 hour ago | parent

Looks like a different version of WSL2 with a newer kernel and newer VM host software

pjmlp 49 minutes ago | parent

An evolution, better said.

Now there is virtio support, finally no need to depend on external CLI tools for what should have been in the box on day on.

Until now, even for Windows containers, we needed some Docker compatible CLI tool.

jesse_dot_id 1 hour ago | parent

I jumped ship from Windows a couple of years ago after having used it since the early 90's. One of the primary reasons was how much I had to fight with WSL2 in my day-to-day work. But now it's becoming even more apparent that Microsoft does not care about its operating system. I don't even know what they could do to get me back. Trust continues to be a huge problem in the AI era of Microsoft.

throwa356262 1 hour ago | parent

WSL has been god send for corporate employees who get a windows laptop but need to do real work.

But everyone knows that performance of WSL is nowhere near native linux on the same machine.

zeryx 17 minutes ago | parent

Honestly the performance hit of WSl even being alive and running in the background of my XPS was so bad I just ssh into a workstation and do everything on there instead. Trying to get windows to just be usable is such a massive pain in the ass.

secondcoming 11 minutes ago | parent

Luckily I'm allowed use Hyper-V for Linux work

pjmlp 4 minutes ago | parent

Guess where WSL runs on?

pjmlp 4 minutes ago | parent

Some of us also do real work on Windows, ask Valve.

shevy-java 48 minutes ago | parent

For me Win11 was the final stop.

I still use Win10 for a few things, including testing stuff works there too, via java. I switched to Linux in 2004 or so, though.

chris_money202 32 minutes ago | parent

Did you work out of /mnt/c?

DiabloD3 23 minutes ago | parent

I suspect they did. 100% of cases where people complain WSL2 was slow and I helped debug was this specific incorrect usage.

shevy-java 49 minutes ago | parent

WSL is one of the few good ideas Microsoft had in the last ... 5000 years or so.

PunchyHamster 40 minutes ago | parent

Amazing they managed to make virtualisation that slow in WSL2