Re: [Starpu-devel] Heft/dmda: locking in compute_all_performance_predictions.

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

Cyril Roelandt, le Thu 22 Nov 2012 17:16:36 +0100, a écrit :
> if (exp_end[worker][nimpl] > max_exp_end)
>         max_exp_end = exp_end[worker][nimpl];
> _STARPU_PTHREAD_MUTEX_UNLOCK(&sched_mutex[worker])
> 
> 
> The exact same code can be found in compute_all_performance_predictions() in
> dmda, except that we do not lock the worker's mutex. Why is that ?

I believe it's simply a bug. One should indeed take the lock, to make
sure to be getting a coherent set of {exp_start, exp_len} values. It
might be useful to only read those in the critical section, or even turn
the mutex into an rwlock.

Samuel