Bug 121129 – NetworkProcess can hit the dispatch thread limit

• Status: ASSIGNED
• Component: WebKit2

[Brady Eidson]

NetworkProcess can hit the dispatch thread limit.

With certain usage patterns we can have 64+ dispatch threads going, and this can hang the network process into an unrecoverable state.

Instead of using a singleton dispatch queue with a high limit, we should use individual queues per-connection with a width of 1.

In radar as <rdar://problem/13913483>

[Brady Eidson]

Created attachment 211255 [details]
Patch v1 

Way too many variables on reproducing this so it's impossible to have a test for.

That said, all tests pass locally and "Basic Browsing Seems To Work™"

[Geoffrey Garen]

Comment on attachment 211255 [details]
Patch v1 

The code here looks right to me.

But why does more queues avoid the dispatch thread limit?

[Brady Eidson]

(In reply to comment #2)
> (From update of attachment 211255 [details])
> The code here looks right to me.
> 
> But why does more queues avoid the dispatch thread limit?

Following up with Geoff IRL.

[Sam Weinig]

(In reply to comment #3)
> (In reply to comment #2)
> > (From update of attachment 211255 [details] [details])
> > The code here looks right to me.
> > 
> > But why does more queues avoid the dispatch thread limit?
> 
> Following up with Geoff IRL.

Will you tell us the answer as well?

[Brady Eidson]

(In reply to comment #4)
> (In reply to comment #3)
> > (In reply to comment #2)
> > > (From update of attachment 211255 [details] [details] [details])
> > > The code here looks right to me.
> > > 
> > > But why does more queues avoid the dispatch thread limit?
> > 
> > Following up with Geoff IRL.
> 
> Will you tell us the answer as well?

Following up with Sam IRL also.

[Anders Carlsson]

(In reply to comment #5)
> (In reply to comment #4)
> > (In reply to comment #3)
> > > (In reply to comment #2)
> > > > (From update of attachment 211255 [details] [details] [details] [details])
> > > > The code here looks right to me.
> > > > 
> > > > But why does more queues avoid the dispatch thread limit?
> > > 
> > > Following up with Geoff IRL.
> > 
> > Will you tell us the answer as well?
> 
> Following up with Sam IRL also.

If possible, it would be nice to have this stored in the bug for future reference. If it’s not possible, please comment in the radar.