Re: [Starpu-devel] Task status invalid

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Hello,

mansouri farouk, le Wed 28 May 2014 11:50:39 +0200, a écrit :
> I use Starpu API to process iterative applications in DSP domain. So, in
> order to re-use the handles (buffers) obtained by "starpu_malloc",

I'm not sure to understand: starpu_malloc returns a buffer, not a
handle.

> I check writers and readers task's status from that handle ( If task
> has a Terminated status ....affect the handle to another new task ).

Either you want to reuse the handle, and for this you just need to make
the new task write to the handle (STARPU_W), and this new task will be
made to wait for all previous tasks before being able to start.

Or you want to reuse the buffer, i.e. you want to unregister a handle,
and register the buffer again and get a new handle. The issue is that
data registration is synchronous, so you would have to make your main
thread wait for the the tasks, by using starpu_data_unregister for
instance.

> So my questions are: - Is it possible (practicable) to do that ? (Affect a
> handles to a new task if the oldest had terminated)

The mere data dependencies of StarPU should be all fine for this.

>                      - What STARPU_TASK_INVALID status of task means after
> it has been executed ?

I don't understand: the status of a task does not become
STARPU_TASK_INVALID at task termination. That being said, if you have
left task->destroy to 1, then on task termination the task structure is
freed, and thus reused for other purpose, which probably has zeroed the
memory area.

Samuel