BEbenreesman·Aug 21, 2022
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
Read the rest
), 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.