Hi Vyacheslav,
I see your point.
I don't use separate Isolate for each thread and all tasks use
function objects compiled in the global Context/Isolate.
This might be a trouble of course, but I was not sure there is a good
way to create a function object
in main Context and then transfer it to another Isolate/Context.
Essentially I wanted to achieve following usage:
// thread function
function foo () {}
// starts execution in a separate thread
task(foo);
I do make them run exclusively (at least I hope I do) by using
Locker locker;
Locker::StartPreemption(preemption_interval);
HandleScope scope;
context = Context::New();
context->Enter();
The code is in a fork from nodejs.You can see the code here:
https://github.com/bfrancojr/node/blob/node-task/src/node_task.cc
The funny part is that if I create just a couple of threads the memory
is stable, while I call V8::IdleNotification() every 5 sec.
If I increase the number of tasks to 100 it will start to grow and
the process will run out memory. However If I start to call
V8::IdleNotification() every 0.3 seconds it fixes it again.
I've got a feeling the v8 treats the GC as one of the tasks, meaning
that the more tasks I create the more time is allocated to 'garbage
producers'
and the smaller is a relative portion of time for GC. May be I am
wrong.
So the questions are:
1. Can I transfer an function object from script compiled in global
context and main thread Isolate into the other thread's Isolate and
execute there?
2. If not, Is what I am doing a valid v8 API usage at all? What could
be other ways to trigger GC more often?
Thanks,
Dennis
On Aug 31, 12:44 am, Vyacheslav Egorov <vego...@chromium.org> wrote:
> Hi Dennis,
>
> V8's GC is stop-the-world type so you don't have to do anything
> special to make it "keep up". If you are getting OOM that most
> probably means you have a leak somewhere. Try tracing GC with
> --trace-gc flag to see how heap grows.
>
> Also you can't run JavaScript in parallel on V8 unless you create
> several isolates.
>
> If you are using a single isolate from many threads you have to ensure
> that only one thread is executing JS at the given moment.
>
> --
> Vyacheslav Egorov
>
> On Wed, Aug 31, 2011 at 2:28 AM, Dennis H <gluck...@gmail.com> wrote:
> > Dear v8 Developers,
>
> > I am relatively new to v8 internals, but here is what I found:
> > I tried to create an app which has multiple tasks running in parallel.
> > The v8::internal::Thread API seems to work fine, the trouble is I
> > didn't find a good way to make garbage collection to keep up.
>
> > I do call the V8::IdleNotification() in the main event loop
> > periodically, but it doesn't scale if number of threads is getting
> > bigger. Essentially If I create a lot of tasks, the process would
> > reliably run out of memory pretty quick.
>
> > How is the garbage collection supposed to be handled correctly with
> > multiple threads?
>
> > I used v3.4.14.
>
> > Thanks,
> > Dennis
>
> > --
> > v8-users mailing list
> > v8-users@googlegroups.com
> >http://groups.google.com/group/v8-users
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