I'm slightly surprised cloudflare isn't using a userspace tcp/ip stack already (faster - less context switches and copies). It's the type of company I'd expect to actually need one.
Nice, they know better. But it also makes me wonder, because they're saying "but what if you need to run another app", I'd expect for things like loadbalancers for example, you'd only run one app per server on the data plane, the user space stack handles that, and the OS/services use a different control plane NIC with the kernel stack so that boxes are reachable even if there is link saturation, ddos,etc..
It also makes me wonder, why is tcp/ip special? The kernel should expose a raw network device. I get physical or layer 2 configuration happening in the kernel, but if it is supposed to do IP, then why stop there, why not TLS as well? Why run a complex network protocol stack in the kernel when you can just expose a configured layer 2 device to a user space process? It sounds like "that's just the way it's always been done" type of a scenario.
You can do that if you want, but I think part of why tcp/ip is a useful layer of abstraction is it allows more robust boundaries between applications that may be running on the same machine. If you're just at layer 2 you are basically acting in behalf of the whole box.
AFAIK Cloudflare runs their whole stack on every machine. I guess that gives them flexibility and maybe better load balancing. They also seem to use only one NIC.
why is tcp/ip special? The kernel should expose a raw network device. ... Why run a complex network protocol stack in the kernel when you can just expose a configured layer 2 device to a user space process?
Check out the MIT Exokernel project and Solarflare OpenOnload that used this approach. It never really caught on because the old school way is good enough for almost everyone.
why stop there, why not TLS as well?
kTLS is a thing now (mostly used by Netflix). Back in the day we also had kernel-mode Web servers to save every cycle.
Aren't neither required these days with the "async" like and zero-copy interfaces that are now available (like io_uring, where it's still handled by the kernel), along with the nearly non-existence of single core processors in modern times?
A few things in the article are Douglas Adams quotes, and more specifically from the Hitchhiker’s Guide series.
Creating the universe being regarded as a mistake and making many unhappy is from those books. Whenever someone figures out the universe it gets replaced with something stranger and having evidence that’s happened repeatedly is too. The Restaurant at the End of the Universe is reference in the article.
I’m a bit surprised nothing in the article was mentioned as being “mostly harmless”.
I had to read their article on "soft-unicast" before I could really grok this one: https://blog.cloudflare.com/cloudflare-servers-dont-own-ips-...
I'm slightly surprised cloudflare isn't using a userspace tcp/ip stack already (faster - less context switches and copies). It's the type of company I'd expect to actually need one.
From 2016: https://blog.cloudflare.com/why-we-use-the-linux-kernels-tcp...
Nice, they know better. But it also makes me wonder, because they're saying "but what if you need to run another app", I'd expect for things like loadbalancers for example, you'd only run one app per server on the data plane, the user space stack handles that, and the OS/services use a different control plane NIC with the kernel stack so that boxes are reachable even if there is link saturation, ddos,etc..
It also makes me wonder, why is tcp/ip special? The kernel should expose a raw network device. I get physical or layer 2 configuration happening in the kernel, but if it is supposed to do IP, then why stop there, why not TLS as well? Why run a complex network protocol stack in the kernel when you can just expose a configured layer 2 device to a user space process? It sounds like "that's just the way it's always been done" type of a scenario.
You can do that if you want, but I think part of why tcp/ip is a useful layer of abstraction is it allows more robust boundaries between applications that may be running on the same machine. If you're just at layer 2 you are basically acting in behalf of the whole box.
AFAIK Cloudflare runs their whole stack on every machine. I guess that gives them flexibility and maybe better load balancing. They also seem to use only one NIC.
why is tcp/ip special? The kernel should expose a raw network device. ... Why run a complex network protocol stack in the kernel when you can just expose a configured layer 2 device to a user space process?
Check out the MIT Exokernel project and Solarflare OpenOnload that used this approach. It never really caught on because the old school way is good enough for almost everyone.
why stop there, why not TLS as well?
kTLS is a thing now (mostly used by Netflix). Back in the day we also had kernel-mode Web servers to save every cycle.
> faster - less context switches and copies
Aren't neither required these days with the "async" like and zero-copy interfaces that are now available (like io_uring, where it's still handled by the kernel), along with the nearly non-existence of single core processors in modern times?
Being a networking company I always wondered why did they pick Linux over FreeBSD.
SLATFATF - "So long and thanks for all the fish" is a Douglas Adams quote
https://en.wikipedia.org/wiki/So_Long,_and_Thanks_for_All_th...
A few things in the article are Douglas Adams quotes, and more specifically from the Hitchhiker’s Guide series.
Creating the universe being regarded as a mistake and making many unhappy is from those books. Whenever someone figures out the universe it gets replaced with something stranger and having evidence that’s happened repeatedly is too. The Restaurant at the End of the Universe is reference in the article.
I’m a bit surprised nothing in the article was mentioned as being “mostly harmless”.