4. dec. 2010 17.56 skrev hua ye <[email protected]>: > Hi Kasper, > > Yes, we use the old version. I checked the new v8 source and the full GC is > removed from creating new context. > Thanks for the reminder. > > Then I have other questions? > 1. It seems that without GC creating context will be faster, but, I wonder > if it just moved the cost from here to other places.
Having fewer GCs will almost always be faster, but of course it will tend to use more memory. There's an idle callback in the API that you can use to tell V8 that now would be a good time to do GC. > 2. What's the reason to remove GC from creating new context? As you noticed it slows down creating a new context. :-) The reason it was there is that new contexts are often created after several old contexts have been disposed and it can be good to do a GC after disposal of a context because it is a time when a lot of garbage can be collected. > 3. Where can I get the benchmark data between different v8 versions? We sometimes publish benchmark data for the whole browser on the Chromium blog, but I don't think we ever published anythink like the data you are asking about. > Kenny > > 2010/12/4 Kasper Lund <[email protected]> >> >> Hua ye, >> >> Which version of V8 are you using? The current version of V8 does not >> invoke the garbage collector when creating new contexts and it hasn't >> since r4003 which was submitted in early March, 2010. >> >> Cheers, >> Kasper >> >> On Sat, Dec 4, 2010 at 6:05 AM, hua ye <[email protected]> wrote: >> > Dears, >> > >> > Is there any way to boost the speed of v8 GC? >> > From my profiling when v8 creates a new context, it will execute a >> > full GC if the old context is disposed. The full GC costs most of the >> > time. >> > >> > Is there any idea to boost this, the following is my profiling result: >> > >> > Persistent<Context> v8::Context::New( >> > v8::ExtensionConfiguration* extensions, >> > v8::Handle<ObjectTemplate> global_template, >> > v8::Handle<Value> global_object) { >> > EnsureInitialized("v8::Context::New()"); >> > LOG_API("Context::New"); >> > ON_BAILOUT("v8::Context::New()", return Persistent<Context>()); >> > >> > // Enter V8 via an ENTER_V8 scope. >> > i::Handle<i::Context> env; >> > { >> > ENTER_V8; >> > #if defined(ANDROID) >> > // On mobile device, full GC is expensive, leave it to the system >> > to >> > // decide when should make a full GC. >> > #else >> > // Give the heap a chance to cleanup if we've disposed contexts. >> > >> > i::Heap::CollectAllGarbageIfContextDisposed(); >> > // >> > ******** Most of the time here >> > #endif >> > >> > ...... >> > ...... >> > ...... >> > >> > // Create the environment. >> > env = >> > i::Bootstrapper::CreateEnvironment( //%%%% >> > % create environment costs also too much time >> > Utils::OpenHandle(*global_object), >> > proxy_template, >> > extensions); >> > >> > // Restore the access check info on the global template. >> > if (!global_template.IsEmpty()) { >> > ASSERT(!global_constructor.is_null()); >> > ASSERT(!proxy_constructor.is_null()); >> > global_constructor->set_access_check_info( >> > proxy_constructor->access_check_info()); >> > global_constructor->set_needs_access_check( >> > proxy_constructor->needs_access_check()); >> > } >> > } >> > // Leave V8. >> > >> > if (env.is_null()) >> > return Persistent<Context>(); >> > return Persistent<Context>(Utils::ToLocal(env)); >> > } >> > >> > -- >> > v8-users mailing list >> > [email protected] >> > http://groups.google.com/group/v8-users >> > >> >> -- >> v8-users mailing list >> [email protected] >> http://groups.google.com/group/v8-users > > -- > v8-users mailing list > [email protected] > http://groups.google.com/group/v8-users -- Erik Corry, Software Engineer Google Denmark ApS - Frederiksborggade 20B, 1 sal, 1360 København K - Denmark - CVR nr. 28 86 69 84 -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users
