Comment by pizlonator
4 months ago
Fil-C running on any x86 box is faster than any CHERI implementation that has ever existed.
That's likely to be true in embedded also, just because of the relationship between volume and performance in silicon. Fil-C runs on the high volume stuff, so it'll get better perf.
CHERI doubles the size of pointers, so it's not like it has a decisive advantage over Fil-C.
Is this your last design iteration? Benchmarks would be great and some performance justification based on the design (techniques).
Are all possible memory problems checked, which to me include those listed in https://matu3ba.github.io/articles/optimal_debugging/#practi... (OOB, null, type confusion, integer overflow, invalid stack access, UUM, data races, illegal aliasing/provenance, stack overflows, ..) ?
Definitely not the last.
There’s so much perf on the table that I haven’t claimed yet.
I’m just focusing on other things most of the time, like right now I want to actually make a super easy to install memory safe sshd distro.
The perf is more than good enough for that so that’s just a thing I should ship
All of the things you list are either checked or they’re given some kind of safe semantics. Like some kinds of type confusion are just fine and need to work (like int to float bit casts)
> right now I want to actually make a super easy to install memory safe sshd distro
That is amazing and looks like an excellent first use case.
> Fil-C running on any x86 box is faster than any CHERI implementation that has ever existed.
Heh. I don't doubt it. Just like RISC-V in QEmu on a x86 box is faster than any RISC-V core that anyone can get their hands on ... but only so far.
> Fil-C running on any x86 box is faster than any CHERI implementation that has ever existed
There are a lot of x86 boxes out there. Is Fil-C really faster on all of them vs. CHERI on Morello?
Yeah
So CHERI makes a 2.5 GHz ARM CPU slower than an underpowered Atom? For what benchmarks?
(Disclosure: I had a ~1GHz? atom mini-PC recently until it bricked. It could technically boot Windows 10 or Linux, but it was not fast.)
Do you think that MTE will make an Apple M5 slower than an Atom as well?
Do you even have access to CHERI hardware Phil?
No, and I don't need to in order to know that my claim is accurate.
Also, the fact that having access to CHERI hardware is a thing you presume I don't have should tell you a lot about how likely CHERI is to ever succeed