Re: [Starpu-devel] Issue with lws

[Samuel Thibault <samuel.thibault@inria.fr>]

Mathieu Faverge, le sam. 15 sept. 2018 15:10:22 +0200, a ecrit:
> Still the same asserts, the others you added are not triggered.

Ok... Did you try with --enable-debug in case the additional assertions
catch something?

Another test worth trying is to disable task stealing by making
select_victim() return -1, but using round-robin push instead of
locality push: in lws_push_task, comment the if this way:

        if (workerid == -1)
                workerid = starpu_worker_get_id();

        /* If the current thread is not a worker but
         * the main thread (-1) or the current worker is not in the target
         * context, we find the better one to put task on its queue */
//      if (workerid == -1 || !starpu_sched_ctx_contains_worker(workerid, 
sched_ctx_id) ||
//                      !starpu_worker_can_execute_task_first_impl(workerid, 
task, NULL))
                workerid = select_worker(task, sched_ctx_id);

so that lws will always select various workers, thus scrambling the task
distribution. If that works too, it's really the task stealing mechanism
which has an issue, even if my glaring the source code didn't let me
find anything odd with it :)

Samuel