prometheus-cpp VS lion

Rust does have some very cool mechanisms for safety, including in the presence of concurrency.

But this thread is generating blowback from someone saying: “slow down there with the hand-rolled atomic operations, you can hand-roll your multi-threaded locking strategy and it’ll be way safer at a modest cost!”

So, probably not the target audience for Rust ;)

I use a lot of C++ still because there are libraries I want and I have a significant investment in existing code, but I’d love to get to something more modern.

Hand-rolled atomics and load/store relaxation in application code make even seasoned C++ hackers a bit nervous: we saw this shit from business logic hackers at FB all the time and my colleague coined the term “aggressively intermediate” for the style.

I don’t mean to pick on the author of a quite good library (and it is quite good), but I ran across this the other day:

https://github.com/jupp0r/prometheus-cpp/blob/master/core/sr...

It’s correct (I think, very easy to be wrong about this sort of thing), but what are we measuring here where we can’t delegate that CAS into pthread? Branch mispredictions?

Either threads are fighting over whatever cache line that’s on (exclusive -> invalid -> exclusive -> invalid), or not. If they are, I’ve just deprived the scheduler of the opportunity to wake me up when the other 59 threads are done. If they’re not, I’ve maybe saved like one line in my L1.

And in something like a metrics library, you could be wrong for a very long time before someone pinned it down.

Some metric collecting tool, for example, Prometheus and its client library for C++

You can use https://github.com/jupp0r/prometheus-cpp (your custom data) in combination with https://grafana.com/ that has plugins for things like cpu usage.

Grafana and Prometheus is what I’d use if you’re deploying this in Kubernetes. I haven’t used the C++ library, but generally you can just add a Prometheus client library (e.g. https://github.com/jupp0r/prometheus-cpp ) which makes it quite easy to instrument your application and expose metrics via HTTP. Then you need to configure Prometheus to scrape metrics from your application.

I've been starting to dabble with digital logic design via Clash (https://clash-lang.org/), and there is a very cool-looking RISC-V SoC project done in that tool that looks fairly serious: https://github.com/standardsemiconductor/lion.

That’s fascinating about the M1. In retrospect it seems like kind of a no-brainer but I doubt I would have thought of it.

SPARC had different memory models at different ISA revs IIRC: it’s been like 20 years since I was dealing with SPARC so I might be misremembering the details. Alpha would have been a better example.

RISC-V is really interesting. I’ve been slowly working through this: https://github.com/standardsemiconductor/lion, highly recommend!

Interesting. Actually, you may be just the person to answer my question: Is it possible/plausible to run a Cardano node on Lion OS on a RISC-V machine? IMO, it would be great for the community if we could run all Cardano stake pools on end to end formally verified machines using open source core and hardware.

Lion: A formally verified, 5-stage pipeline RISC-V core\ (30 comments)

In addition, you can actually set the riscv-formal suite to verify correctness by k-induction: https://github.com/SymbioticEDA/riscv-formal/pull/28 https://symbiyosys.readthedocs.io/en/latest/quickstart.html#beyond-bounded-model-checks although I concur that by looking at https://github.com/standardsemiconductor/lion/blob/main/lion-formal/app/Main.hs the lion core is only verified with BMC.