https://hal.archives-ouvertes.fr/hal-02443512
Tip revision: 31be198773f103324593d26369f135fbde5b97f8 authored by Software Heritage on 20 January 2020, 08:58:55 UTC
hal: Deposit 359 in collection hal
hal: Deposit 359 in collection hal
Tip revision: 31be198
starpu_task_dep.h
/* StarPU --- Runtime system for heterogeneous multicore architectures.
*
* Copyright (C) 2011-2017 Inria
* Copyright (C) 2009-2018 Université de Bordeaux
* Copyright (C) 2010-2015,2017,2018,2019 CNRS
* Copyright (C) 2011 Télécom-SudParis
* Copyright (C) 2016 Uppsala University
*
* StarPU is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2.1 of the License, or (at
* your option) any later version.
*
* StarPU is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
*
* See the GNU Lesser General Public License in COPYING.LGPL for more details.
*/
#ifndef __STARPU_TASK_DEP_H__
#define __STARPU_TASK_DEP_H__
#include <starpu.h>
#ifdef __cplusplus
extern "C"
{
#endif
/**
@defgroup API_Explicit_Dependencies Explicit Dependencies
@{
*/
/**
Declare task dependencies between a \p task and an array of tasks
of length \p ndeps. This function must be called prior to the
submission of the task, but it may called after the submission or
the execution of the tasks in the array, provided the tasks are
still valid (i.e. they were not automatically destroyed). Calling
this function on a task that was already submitted or with an entry
of \p task_array that is no longer a valid task results in an
undefined behaviour. If \p ndeps is 0, no dependency is added. It
is possible to call starpu_task_declare_deps_array() several times
on the same task, in this case, the dependencies are added. It is
possible to have redundancy in the task dependencies.
*/
void starpu_task_declare_deps_array(struct starpu_task *task, unsigned ndeps, struct starpu_task *task_array[]);
/**
Declare task dependencies between a \p task and an series of \p
ndeps tasks, similarly to starpu_task_declare_deps_array(), but the
tasks are passed after \p ndeps, which indicates how many tasks \p
task shall be made to depend on. If \p ndeps is 0, no dependency is
added.
*/
void starpu_task_declare_deps(struct starpu_task *task, unsigned ndeps, ...);
/**
Declare task end dependencies between a \p task and an array of
tasks of length \p ndeps. \p task will appear as terminated not
only when \p task is termination, but also when the tasks of \p
task_array have terminated. This function must be called prior to
the termination of the task, but it may called after the submission
or the execution of the tasks in the array, provided the tasks are
still valid (i.e. they were not automatically destroyed). Calling
this function on a task that was already terminated or with an
entry of \p task_array that is no longer a valid task results in an
undefined behaviour. If \p ndeps is 0, no dependency is added. It
is possible to call starpu_task_declare_end_deps_array() several
times on the same task, in this case, the dependencies are added.
It is currently not implemented to have redundancy in the task
dependencies.
*/
void starpu_task_declare_end_deps_array(struct starpu_task *task, unsigned ndeps, struct starpu_task *task_array[]);
/**
Declare task end dependencies between a \p task and an series of \p
ndeps tasks, similarly to starpu_task_declare_end_deps_array(), but
the tasks are passed after \p ndeps, which indicates how many tasks
\p task 's termination shall be made to depend on. If \p ndeps is
0, no dependency is added.
*/
void starpu_task_declare_end_deps(struct starpu_task *task, unsigned ndeps, ...);
/**
Fill \p task_array with the list of tasks which are direct children
of \p task. \p ndeps is the size of \p task_array. This function
returns the number of direct children. \p task_array can be set to
<c>NULL</c> if \p ndeps is 0, which allows to compute the number of
children before allocating an array to store them. This function
can only be called if \p task has not completed yet, otherwise the
results are undefined. The result may also be outdated if some
additional dependency has been added in the meanwhile.
*/
int starpu_task_get_task_succs(struct starpu_task *task, unsigned ndeps, struct starpu_task *task_array[]);
/**
Behave like starpu_task_get_task_succs(), except that it only
reports tasks which will go through the scheduler, thus avoiding
tasks with not codelet, or with explicit placement.
*/
int starpu_task_get_task_scheduled_succs(struct starpu_task *task, unsigned ndeps, struct starpu_task *task_array[]);
/**
Add \p nb_deps end dependencies to the task \p t. This means the
task will not terminate until the required number of calls to the
function starpu_task_end_dep_release() has been made.
*/
void starpu_task_end_dep_add(struct starpu_task *t, int nb_deps);
/**
Unlock 1 end dependency to the task \p t. This function must be
called after starpu_task_end_dep_add().
*/
void starpu_task_end_dep_release(struct starpu_task *t);
/**
Define a task logical identifer. It is possible to associate a task
with a unique <em>tag</em> chosen by the application, and to
express dependencies between tasks by the means of those tags. To
do so, fill the field starpu_task::tag_id with a tag number (can be
arbitrary) and set the field starpu_task::use_tag to 1. If
starpu_tag_declare_deps() is called with this tag number, the task
will not be started until the tasks which holds the declared
dependency tags are completed.
*/
typedef uint64_t starpu_tag_t;
/**
Specify the dependencies of the task identified by tag \p id. The
first argument specifies the tag which is configured, the second
argument gives the number of tag(s) on which \p id depends. The
following arguments are the tags which have to be terminated to
unlock the task. This function must be called before the associated
task is submitted to StarPU with starpu_task_submit().
<b>WARNING! Use with caution</b>. Because of the variable arity of
starpu_tag_declare_deps(), note that the last arguments must be of
type ::starpu_tag_t : constant values typically need to be
explicitly casted. Otherwise, due to integer sizes and argument
passing on the stack, the C compiler might consider the tag
<c>0x200000003</c> instead of <c>0x2</c> and <c>0x3</c> when
calling <c>starpu_tag_declare_deps(0x1, 2, 0x2, 0x3)</c>. Using the
starpu_tag_declare_deps_array() function avoids this hazard.
\code{.c}
// Tag 0x1 depends on tags 0x32 and 0x52
starpu_tag_declare_deps((starpu_tag_t)0x1, 2, (starpu_tag_t)0x32, (starpu_tag_t)0x52);
\endcode
*/
void starpu_tag_declare_deps(starpu_tag_t id, unsigned ndeps, ...);
/**
Similar to starpu_tag_declare_deps(), except that its does not take
a variable number of arguments but an \p array of tags of size \p
ndeps.
\code{.c}
// Tag 0x1 depends on tags 0x32 and 0x52
starpu_tag_t tag_array[2] = {0x32, 0x52};
starpu_tag_declare_deps_array((starpu_tag_t)0x1, 2, tag_array);
\endcode
*/
void starpu_tag_declare_deps_array(starpu_tag_t id, unsigned ndeps, starpu_tag_t *array);
/**
Block until the task associated to tag \p id has been executed.
This is a blocking call which must therefore not be called within
tasks or callbacks, but only from the application directly. It is
possible to synchronize with the same tag multiple times, as long
as the starpu_tag_remove() function is not called. Note that it is
still possible to synchronize with a tag associated to a task for
which the strucuture starpu_task was freed (e.g. if the field
starpu_task::destroy was enabled).
*/
int starpu_tag_wait(starpu_tag_t id);
/**
Similar to starpu_tag_wait() except that it blocks until all the \p
ntags tags contained in the array \p id are terminated.
*/
int starpu_tag_wait_array(unsigned ntags, starpu_tag_t *id);
/**
Clear the <em>already notified</em> status of a tag which is not
associated with a task. Before that, calling
starpu_tag_notify_from_apps() again will not notify the successors.
After that, the next call to starpu_tag_notify_from_apps() will
notify the successors.
*/
void starpu_tag_restart(starpu_tag_t id);
/**
Release the resources associated to tag \p id. It can be called
once the corresponding task has been executed and when there is no
other tag that depend on this tag anymore.
*/
void starpu_tag_remove(starpu_tag_t id);
/**
Explicitly unlock tag \p id. It may be useful in the case of
applications which execute part of their computation outside StarPU
tasks (e.g. third-party libraries). It is also provided as a
convenient tool for the programmer, for instance to entirely
construct the task DAG before actually giving StarPU the
opportunity to execute the tasks. When called several times on the
same tag, notification will be done only on first call, thus
implementing "OR" dependencies, until the tag is restarted using
starpu_tag_restart().
*/
void starpu_tag_notify_from_apps(starpu_tag_t id);
struct starpu_task *starpu_tag_get_task(starpu_tag_t id);
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* __STARPU_TASK_DEP_H__ */