Hello Mateusz,
On 09/10/17(Mon) 21:43, Mateusz Guzik wrote:
> I was looking at rw lock code out of curiosity and noticed you always do
> membar_enter which on MP-enabled amd64 kernel translates to mfence.
> This makes the entire business a little bit slower.
>
> Interestingly you already have relevant macros for amd64:
> #define membar_enter_after_atomic() __membar("")
> #define membar_exit_before_atomic() __membar("")
If you look at the history, you'll see that theses macro didn't exist
when membar_* where added to rw locks.
> And there is even a default variant for archs which don't provide one.
> I guess the switch should be easy.
Then please do it :) At lot of stuff is easy on OpenBSD but we are not
enough.
Do it, test it, explain it, get oks and commit it 8)
