On Tue, Jun 20, 2023 at 3:36 PM robert engels <reng...@ix.netcom.com> wrote: > > Since this is an initialization guard - can’t it simply be double checked > with an atomic flag?
That would be a good first thing to try. Ian > > On Jun 20, 2023, at 9:04 AM, Ian Lance Taylor <i...@golang.org> wrote: > > > > On Tue, Jun 20, 2023 at 5:32 AM Bảo Phan Quốc <phq...@gmail.com> wrote: > >> > >> I'm using cgo to call a C function from Go. Inside the C function there is > >> a callback to a Go function. In other way, I'm calling Go -> C -> Go. > >> > >> After running pprof, I noticed that the __GI___pthread_mutex_unlock took > >> half of the execution time. AFAIK, cgo has an overhead, especially calling > >> back from C to Go. But it's weird that cgo takes half of the execution > >> time to do some locking. Is there something wrong in my code? > > > > Every call from C to Go does acquire a mutex to check that the Go > > runtime has been fully initialized. This is normally not a big deal > > as the mutex is held only briefly. But your code does a lot of > > parallel calls from C to Go. It is possible that the heavy contention > > on the mutex is causing the results that you are seeing. > > > > The code in question is the C function _cgo_wait_runtime_init_done in > > runtime/gco/gcc_libinit.c. It might be possible to speed it up in > > some way to avoid the mutex in the normal case. > > > > Ian > > > > -- > > 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/CAOyqgcU7Csb_hf5gvy8dVHKEHd8GFkN-fUML18uW0HiQGOAXyg%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/CAOyqgcWDPzyR9wS8na6eexkeLtus%2BTWCjsmVObuj8QgD95rJ-Q%40mail.gmail.com.
