[snvzz]

The name-calling is uncalled for.

To elaborate, seL4 claims to be the fastest kernel around[0], a claim that remains unchallenged.

To put it into context, the difference in IPC speed is such that you'd need an order of magnitude more IPC for a multiserver system based on seL4 to actually be slower than Linux.

A multiserver design would imply increased IPC use, but not an order of magnitude.

0. https://trustworthy.systems/projects/seL4/

[camgunz]

Sorry I'm pretty naive to this space. I didn't immediately see any performance info on that page save for this paper [0] which shows seL4 competitive with NetBSD, but far from Linux. Is there something else I should look at?

[0]: https://trustworthy.systems/publications/full_text/Elphinsto...

[b112]

The name-calling is uncalled for.

From an observer on the sidelines: there was no namecalling.

He said you trolled, not that you ate a troll. The distinction is important.

Even the best of us troll, sometimes. (Not claiming you did btw, just that there was no name calling.)

[saagarjha]

No, it doesn’t. Here’s the full quote from their website:

> seL4 is the world’s fastest operating system kernel designed for security and safety

Linux is arguably not designed for security and safety but it blows seL4 out of the water when it comes to performance. There’s a reason it only gets used in contexts where security is critical; I would have expected that you would be aware of this considering you were the one who is promoting it.

[snvzz]

>but it blows seL4 out of the water when it comes to performance.

Citation needed.

And by that I mean actual benchmarks of Linux doing the few tasks seL4 does, such as IPC or context switching, faster than seL4.

[saagarjha]

No, you don’t get to define the benchmarks like that. People use an OS so they can run real-world programs on top of it, not spin it in a loop and see how fast it can do IPC. In a monolithic kernel there’s no need to switch contexts for many things; that’s the entire point of using one. I’m sure that seL4 has a perfectly fast implementation of those operations but that’s because it sits and does those all day as part of its basic functionality. Optimizing overhead doesn’t win you extra points when you’re comparing against an OS that doesn’t have it all.

[snvzz]

seL4 is an order of magnitude faster at this "overhead" thing. We're talking nanoseconds vs microseconds difference.

The multiserver architecture does indeed imply an elevated use of IPC, but it does in no way outweigh the difference in IPC cost.

In this model, data sharing, and the implied locking, is minimized, which as a consequence helps SMP scaling.

Dragonfly, while not multiserver proper, took a different direction than Freebsd and Linux by optimizing IPC and not implementing fine-grained locks, and instead favoring concurrent lockless and lockfree servers.

As a consequence, Dragonfly scales much better than Freebsd, and in many benchmarks manages to outperform Linux.

This is despite the tiny development team, particularly so when considered relative to the amount of funding these two systems get.

I am sickened by the effort that's being wasted on a model that we know is bad and does not work. Linux will never be high assurance, secure or scale past a certain point.

Fortunately, no matter how long it'll take, the better technology will win; there's no "performance hack" that a bad system can pull to catch up with the better technology once it's there.

Just a matter of time.

[arp242]

> To elaborate, seL4 claims to be the fastest kernel around[0], a claim that remains unchallenged.

Can I run Firefox or PostgreSQL on seL4? Or another real-world program of comparable complexity? And how does the performance of that compare to Linux or BSD?

That's really the only benchmark that matters; it's not hard to be fast if your kernel is simple, but simple is often also less useful. Terry Davis claimed TempleOS was faster than Linux, and in some ways he was right too. But TempleOS is also much more limited than Linux and, in the end, not all that useful – even Terry ran it inside a VM.

I've heard these sort of claims about seL4 before, and I've tried to look up some more detailed information about seL4 before, and I've never really found anything convincing on the topic beyond "TempleOS can do loads more context switches than Linux!" type stuff.