Messages in this thread |  | | Date | Fri, 1 Nov 1996 12:58:24 +0200 (EET) | From | Linus Torvalds <> | Subject | Re: unusual startup messages |
| |
On Thu, 31 Oct 1996, Mark H. Wood wrote: > > [Regarding crypto code in the kernel for IPsec] > [Rustling noise, as of Nomex jumpsuit being donned] > > Okay, why is the network inside the kernel anyway?
Because it can't be done anywhere else..
Yes, you can do it in user space, but your performance will suck unless you ignore security issues or have special hardware (and the special hardware would essentially have to do 90% of the stuff we do in kernel space now: I'm talking _really_ special hardware).
It's been talked about (favourite thing in microkernels is to move critical resources to places they don't belong ;), but I doubt _anybody_ seriously thinks that it can be done in user space while keeping up with things like HIPPI and having full memory protection.
Oh, and the big problem isn't throughput: you can essentially get throughput by having large buffers (modulo the problems with maxing out your memory bandwidth which in itself is a large problem). The _big_ problem is latency.
In short, forget about networking in user space unless you're talking >10ms latencies and <10Mbps throughput. 10Mbps ethernet may still be realistic in user space. Just. But the world is moving to 100Mbps and beyond.
Linus
|  |