Re: [gomp4.1] fix more scheduling inconsistencies and add verification routines

[Aldy Hernandez <aldyh at redhat dot com>]

On 10/04/2015 10:26 AM, Aldy Hernandez wrote:

> However magically this happened before :), my attached changes to
> gomp_task_run_pre() will move this task to the end of the queue such
> that the WAITING tasks are first.

FWIW, thinking about this some more, I suppose setting a task to 
GOMP_TASK_TIED by iterating through its sibling queue could render the 
taskgroup queue into an indeterminate state, by leaving the taskgroup 
with TIED tasks before WAITING tasks.  And vice versa, removing from 
taskgroup could leave the sibling queue confused.

However... since we remove the child_task from the team->task_queue 
altogether in gomp_task_run_pre(), the team->task_queue will still be 
sane and barrier picking should work.  I suppose what's happening is 
that if we mess up the child or taskgroup queues, barrier picking will 
still pick stuff up. ??

Also, sibling and taskgroup queues are created by inserting things at 
the top, while the team's task_queue is populated by inserting at the 
end.  So barrier and child/taskgroup picking are working in opposite orders.

...or some combination of the above.  Either way, I say we've been 
lucky.  I still think we should fix those links as per my patch.

Aldy