I tend to think it should print 1, as well this one: https://go.dev/play/p/bax7CoaSV1d
On Monday, August 15, 2022 at 3:34:35 PM UTC+8 tapi...@gmail.com wrote: > It would be good if the Memory Model article shows some atomic examples. > > On Monday, August 15, 2022 at 3:06:58 PM UTC+8 ma...@changkun.de wrote: > >> I think the new memory model does not guarantee this program always >> prints 1: >> >> 1. There is no synchronization guarantee between line 13 and line 14 >> as these atomic operations are manipulated on the different memory >> locations. >> 2. It is *not* prohibited for the compiler to switch line 13 and line >> 14 (as I read from section https://go.dev/ref/mem#badcompiler) because >> of the above reason, and also, there is no order between line 13 and >> line 20. So this is possible: line 14 < line 18 < line 20 < line 13. >> 3. Depending on the memory layout of a and b, if they are on the same >> cache line, then the program will always print 1. >> >> >> On Mon, Aug 15, 2022 at 8:48 AM 'Axel Wagner' via golang-nuts >> <golan...@googlegroups.com> wrote: >> > >> > Why wouldn't it? >> >> >> >> If the effect of an atomic operation A is observed by atomic operation >> B, then A is synchronized before B. >> > >> > To me, it seems pretty clear that it will. Line 13 is synchronized >> before line 14, which is synchronized before any load observing its effects >> (i.e. any execution of line 18 which runs into the branch) - and such a >> load is synchronized before the load in line 20. >> > >> > Therefore, the store in Line 13 is synchronized before the load in line >> 20. >> > >> > >> > On Mon, Aug 15, 2022 at 8:37 AM tapi...@gmail.com <tapi...@gmail.com> >> wrote: >> >> >> >> By the latest version of Go Memory Model article: >> https://go.dev/ref/mem, will the following program always print 1? >> >> >> >> https://go.dev/play/p/RICYGip5y8M >> >> >> >> -- >> >> You received this message because you are subscribed to the Google >> Groups "golang-nuts" group. >> >> To unsubscribe from this group and stop receiving emails from it, send >> an email to golang-nuts...@googlegroups.com. >> >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/4d9b8130-d06c-4519-9b99-d161e922d8f6n%40googlegroups.com >> . >> > >> > -- >> > You received this message because you are subscribed to the Google >> Groups "golang-nuts" group. >> > To unsubscribe from this group and stop receiving emails from it, send >> an email to golang-nuts...@googlegroups.com. >> > To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/CAEkBMfHpwchwjAMtXNtpVmhb42Ncw9ENKhz5xH9Sv1z_-DMrRA%40mail.gmail.com >> . >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/0ea1f1a1-fee3-4c2a-8dcb-f7bbbc946812n%40googlegroups.com.
