Hi Andrew! Could you please file a bug at crbug.com/v8 with steps to reproduce? We will take a look and see if we can optimize this case.
Until it is fixed, I think caching the backing store pointer in the internal field would work. Then you'd need to ensure that you keep a handle to ArrayBuffer while using the pointer (to prevent ArrayBuffer from being garbage collected). Additionally, the pointer may become invalid if ArrayBuffer is detached. You can detect that case by checking ByteLength() == 0. Cheers, Ulan. On Sun, Oct 18, 2020 at 12:45 AM billywhizz <apjohn...@gmail.com> wrote: > Hi, > > I have put some details here on an issue i have come across while doing > some benchmarking: > https://gist.github.com/billywhizz/ff4c83c37142198d2e70992e438bf045 > > I have a few questions around this: > > 1) Do we need a pthread_mutex_lock and pthread_mutex_unlock in every > access to ArrayBuffer->GetBackingStore? In the absence of a deep dive into > the code (which I will do soon hopefully) I am guessing this is in case the > GC, which is running on another thread, has moved the backing data > elsewhere. > > 2) If i want to access backing data at high frequency from JS (e.g. doing > lots of writing or reading of an arraybuffer on a socket) is it possible > (or advisable) to do something like this in order to avoid the lock > contention in GetBackingStore? > https://gist.github.com/billywhizz/ff4c83c37142198d2e70992e438bf045#file-test-cc. > i.e. cache the pointer to the backing data in an internal field, assuming > it will not be moved. > > 3) If the approach in 2) is not possible, is there a known approach to > this problem which can avoid all the syscall overhead of locking the mutex? > > If you need more info or something easy to reproduce please let me know. > > Many Thanks, > > Andrew > > -- > -- > v8-users mailing list > v8-users@googlegroups.com > http://groups.google.com/group/v8-users > --- > You received this message because you are subscribed to the Google Groups > "v8-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to v8-users+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/v8-users/a4ea069b-4271-4590-af99-4446a6a041e4n%40googlegroups.com > <https://groups.google.com/d/msgid/v8-users/a4ea069b-4271-4590-af99-4446a6a041e4n%40googlegroups.com?utm_medium=email&utm_source=footer> > . > -- -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users --- You received this message because you are subscribed to the Google Groups "v8-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to v8-users+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/v8-users/CABNJt2LxOnoPKOjKss-xMo0Dcxcg6HqsQfmMRGwMjF2CfSB1Gw%40mail.gmail.com.
