On Thu, Mar 27, 2014 at 2:58 PM, Ben Noordhuis <[email protected]> wrote:
> On Thu, Mar 27, 2014 at 1:40 PM, Sven Panne <[email protected]> > wrote: > > We will continue to improve the whole API, especially regarding the > > confusing notions of "default Isolate" and "current Isolate". In the > future, > > as a rule of thumb, an embedder should be prepared to have an explicit > > Isolate at hand when one is needed, and you have to care for the > > creation/destruction of Isolates explicitly. Magically creating a VM > > instance before main() and relying on thread-local storage all over the > > place is a constant source of bugs and confusion. Making the VM lifetime > > explicit and having no notion of TLS in v8 will greatly simplify and > > robustify things. This is how it should have been done in the first > place, > > but given the complexity of our code and the code of our embedders, the > > transition is not easy and will take some time. > > I cheer you on from the sidelines but I have to point out that moving > away from thread-local storage will irredeemably break the popular > node-fibers module[1] (used in Cloud9 IDE[2], Meteor[3], etc., not to > mention thousands of in-house applications.) > > Its "fibers" (coroutines) work by saving and restoring V8's > thread-local state whenever the fiber yields. That tricks V8 into > thinking that it runs in another system thread and that allows > multiple concurrent (if not parallel) threads of execution. It's a > terrible hack but hey, it _does_ work. > This change would actually make something like this much cleaner. You don't have to swap the TLS underneath V8 anymore, instead you just use enter and exit the isolate. V8 won't care from which thread you do this, since the Isolate* object will carry all the state V8 needs. best -jochen > > I'm not saying that's a reason to stop improving V8 but I'm sure many > people would appreciate a way going forward. > > [1] https://github.com/laverdet/node-fibers > [2] https://c9.io/ > [3] https://www.meteor.com/ > > -- > -- > v8-users mailing list > [email protected] > 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 [email protected]. > For more options, visit https://groups.google.com/d/optout. > -- -- v8-users mailing list [email protected] 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 [email protected]. For more options, visit https://groups.google.com/d/optout.
