starpu-max/doc/doxygen/chapters/api/initialization.doxy

/*
 * This file is part of the StarPU Handbook.
 * Copyright (C) 2009--2011  Universit@'e de Bordeaux
 * Copyright (C) 2010, 2011, 2012, 2013, 2014  Centre National de la Recherche Scientifique
 * Copyright (C) 2011, 2012 Institut National de Recherche en Informatique et Automatique
 * See the file version.doxy for copying conditions.
 */

/*! \defgroup API_Initialization_and_Termination Initialization and Termination

\struct starpu_driver
structure for a driver
\ingroup API_Initialization_and_Termination
\var enum starpu_worker_archtype starpu_driver::type
The type of the driver. Only ::STARPU_CPU_WORKER,
::STARPU_CUDA_WORKER and ::STARPU_OPENCL_WORKER are currently supported.
\var union starpu_driver::id
The identifier of the driver.

\struct starpu_conf
\ingroup API_Initialization_and_Termination
This structure is passed to the starpu_init() function in order to
configure StarPU. It has to be initialized with starpu_conf_init().
When the default value is used, StarPU automatically selects the
number of processing units and takes the default scheduling policy.
The environment variables overwrite the equivalent parameters.
\var int starpu_conf::magic
\private
Will be initialized by starpu_conf_init(). Should not be set by hand.
\var const char*starpu_conf::sched_policy_name
This is the name of the scheduling policy. This can also be specified
with the environment variable \ref STARPU_SCHED. (default = NULL).
\var struct starpu_sched_policy *starpu_conf::sched_policy
This is the definition of the scheduling policy. This field is ignored
if starpu_conf::sched_policy_name is set. (default = NULL)
\var int starpu_conf::ncpus
This is the number of CPU cores that StarPU can use. This can also be
specified with the environment variable \ref STARPU_NCPU . (default = -1)
\var int starpu_conf::ncuda
This is the number of CUDA devices that StarPU can use. This can also
be specified with the environment variable \ref STARPU_NCUDA. (default =
-1)
\var int starpu_conf::nopencl
This is the number of OpenCL devices that StarPU can use. This can
also be specified with the environment variable \ref STARPU_NOPENCL.
(default = -1)
\var int starpu_conf::nmic
This is the number of MIC devices that StarPU can use. This can also
be specified with the environment variable \ref STARPU_NMIC.
(default = -1)
\var int starpu_conf::nscc
This is the number of SCC devices that StarPU can use. This can also
be specified with the environment variable \ref STARPU_NSCC.
(default = -1)

\var unsigned starpu_conf::use_explicit_workers_bindid
If this flag is set, the starpu_conf::workers_bindid array indicates
where the different workers are bound, otherwise StarPU automatically
selects where to bind the different workers. This can also be
specified with the environment variable \ref STARPU_WORKERS_CPUID. (default = 0)
\var unsigned starpu_conf::workers_bindid[STARPU_NMAXWORKERS]
If the starpu_conf::use_explicit_workers_bindid flag is set, this
array indicates where to bind the different workers. The i-th entry of
the starpu_conf::workers_bindid indicates the logical identifier of
the processor which should execute the i-th worker. Note that the
logical ordering of the CPUs is either determined by the OS, or
provided by the hwloc library in case it is available.
\var unsigned starpu_conf::use_explicit_workers_cuda_gpuid
If this flag is set, the CUDA workers will be attached to the CUDA
devices specified in the starpu_conf::workers_cuda_gpuid array.
Otherwise, StarPU affects the CUDA devices in a round-robin fashion.
This can also be specified with the environment variable \ref
STARPU_WORKERS_CUDAID. (default = 0)
\var unsigned starpu_conf::workers_cuda_gpuid[STARPU_NMAXWORKERS]
If the starpu_conf::use_explicit_workers_cuda_gpuid flag is set, this
array contains the logical identifiers of the CUDA devices (as used by
cudaGetDevice()).
\var unsigned starpu_conf::use_explicit_workers_opencl_gpuid
If this flag is set, the OpenCL workers will be attached to the OpenCL
devices specified in the starpu_conf::workers_opencl_gpuid array.
Otherwise, StarPU affects the OpenCL devices in a round-robin fashion.
This can also be specified with the environment variable \ref
STARPU_WORKERS_OPENCLID. (default = 0)
\var unsigned starpu_conf::workers_opencl_gpuid[STARPU_NMAXWORKERS]
If the starpu_conf::use_explicit_workers_opencl_gpuid flag is set,
this array contains the logical identifiers of the OpenCL devices to
be used.
\var unsigned starpu_conf::use_explicit_workers_mic_deviceid
If this flag is set, the MIC workers will be attached to the MIC
devices specified in the array starpu_conf::workers_mic_deviceid.
Otherwise, StarPU affects the MIC devices in a round-robin fashion.
This can also be specified with the environment variable \ref
STARPU_WORKERS_MICID.
(default = 0)
\var unsigned starpu_conf::workers_mic_deviceid[STARPU_NMAXWORKERS]
If the flag starpu_conf::use_explicit_workers_mic_deviceid is set, the
array contains the logical identifiers of the MIC devices to be used.
\var unsigned starpu_conf::use_explicit_workers_scc_deviceid
If this flag is set, the SCC workers will be attached to the SCC
devices specified in the array starpu_conf::workers_scc_deviceid.
(default = 0)
\var unsigned starpu_conf::workers_scc_deviceid[STARPU_NMAXWORKERS]
If the flag starpu_conf::use_explicit_workers_scc_deviceid is set, the
array contains the logical identifiers of the SCC devices to be used.
Otherwise, StarPU affects the SCC devices in a round-robin fashion.
This can also be specified with the environment variable \ref
STARPU_WORKERS_SCCID.

\var int starpu_conf::bus_calibrate
If this flag is set, StarPU will recalibrate the bus.  If this value
is equal to <c>-1</c>, the default value is used.  This can also be
specified with the environment variable \ref STARPU_BUS_CALIBRATE. (default
= 0)
\var int starpu_conf::calibrate
If this flag is set, StarPU will calibrate the performance models when
executing tasks. If this value is equal to <c>-1</c>, the default
value is used. If the value is equal to <c>1</c>, it will force
continuing calibration. If the value is equal to <c>2</c>, the
existing performance models will be overwritten. This can also be
specified with the environment variable \ref STARPU_CALIBRATE. (default =
0)
\var int starpu_conf::single_combined_worker
By default, StarPU executes parallel tasks
concurrently. Some parallel libraries (e.g. most OpenMP
implementations) however do not support concurrent calls to
parallel code. In such case, setting this flag makes StarPU
only start one parallel task at a time (but other CPU and
GPU tasks are not affected and can be run concurrently).
The parallel task scheduler will however
still try varying combined worker sizes to look for the
most efficient ones. This can also be specified with the environment
variable \ref STARPU_SINGLE_COMBINED_WORKER.
(default = 0)

\var char *starpu_conf::mic_sink_program_path
Path to the kernel to execute on the MIC device, compiled for MIC
architecture. When set to NULL, StarPU automatically looks next to the
host program location.
(default = NULL)

\var int starpu_conf::disable_asynchronous_copy
This flag should be set to 1 to disable
asynchronous copies between CPUs and all accelerators. This
can also be specified with the environment variable \ref
STARPU_DISABLE_ASYNCHRONOUS_COPY. The
AMD implementation of OpenCL is known to fail when copying
data asynchronously. When using this implementation, it is
therefore necessary to disable asynchronous data transfers.
This can also be specified at compilation time by giving to
the configure script the option
\ref disable-asynchronous-copy "--disable-asynchronous-copy". (default = 0)
\var int starpu_conf::disable_asynchronous_cuda_copy
This flag should be set to 1 to disable
asynchronous copies between CPUs and CUDA accelerators.
This can also be specified with the environment variable
\ref STARPU_DISABLE_ASYNCHRONOUS_CUDA_COPY.
This can also be specified at compilation time by giving to
the configure script the option
\ref disable-asynchronous-cuda-copy "--disable-asynchronous-cuda-copy". (default = 0)
\var int starpu_conf::disable_asynchronous_opencl_copy
This flag should be set to 1 to disable
asynchronous copies between CPUs and OpenCL accelerators.
This can also be specified with the environment
variable \ref STARPU_DISABLE_ASYNCHRONOUS_OPENCL_COPY. The AMD
implementation of OpenCL is known to fail
when copying data asynchronously. When using this
implementation, it is therefore necessary to disable
asynchronous data transfers. This can also be specified at
compilation time by giving to the configure script the
option \ref disable-asynchronous-opencl-copy "--disable-asynchronous-opencl-copy".
(default = 0)
\var int starpu_conf::disable_asynchronous_mic_copy
This flag should be set to 1 to disable asynchronous copies between
CPUs and MIC accelerators. This can also be specified with the
environment variable \ref STARPU_DISABLE_ASYNCHRONOUS_MIC_COPY.
This can also be specified at compilation time by giving to the
configure script the option \ref disable-asynchronous-mic-copy "--disable-asynchronous-mic-copy".
(default = 0).

\var unsigned *starpu_conf::cuda_opengl_interoperability
Enable CUDA/OpenGL interoperation on these CUDA
devices. This can be set to an array of CUDA device
identifiers for which cudaGLSetGLDevice() should be called
instead of cudaSetDevice(). Its size is specified by the
starpu_conf::n_cuda_opengl_interoperability field below
(default = NULL)
\var unsigned starpu_conf::n_cuda_opengl_interoperability
todo

\var struct starpu_driver *starpu_conf::not_launched_drivers
Array of drivers that should not be launched by
StarPU. The application will run in one of its own
threads. (default = NULL)
\var unsigned starpu_conf::n_not_launched_drivers
The number of StarPU drivers that should not be
launched by StarPU. (default = 0)
\var starpu_conf::trace_buffer_size
Specifies the buffer size used for FxT tracing.
Starting from FxT version 0.2.12, the buffer will
automatically be flushed when it fills in, but it may still
be interesting to specify a bigger value to avoid any
flushing (which would disturb the trace).

\fn int starpu_init(struct starpu_conf *conf)
\ingroup API_Initialization_and_Termination
This is StarPU initialization method, which must be called prior to
any other StarPU call. It is possible to specify StarPU’s
configuration (e.g. scheduling policy, number of cores, ...) by
passing a non-null argument. Default configuration is used if the
passed argument is NULL. Upon successful completion, this function
returns 0. Otherwise, -ENODEV indicates that no worker was available
(so that StarPU was not initialized).

\fn int starpu_initialize(struct starpu_conf *user_conf, int *argc, char ***argv)
\ingroup API_Initialization_and_Termination
This is the same as starpu_init(), but also takes the \p argc and \p
argv as defined by the application. This is needed for SCC execution
to initialize the communication library.
Do not call starpu_init() and starpu_initialize() in the
same program.

\fn int starpu_conf_init(struct starpu_conf *conf)
\ingroup API_Initialization_and_Termination
This function initializes the conf structure passed as argument with
the default values. In case some configuration parameters are already
specified through environment variables, starpu_conf_init() initializes
the fields of the structure according to the environment variables.
For instance if \ref STARPU_CALIBRATE is set, its value is put in the
field starpu_conf::calibrate of the structure passed as argument. Upon successful
completion, this function returns 0. Otherwise, -EINVAL indicates that
the argument was NULL.

\fn void starpu_shutdown(void)
\ingroup API_Initialization_and_Termination
This is StarPU termination method. It must be called at the end of the
application: statistics and other post-mortem debugging information
are not guaranteed to be available until this method has been called.

\fn void starpu_pause(void)
\ingroup API_Initialization_and_Termination
This call is used to suspend the processing of new tasks by
workers. It can be used in a program where StarPU is used during only
a part of the execution. Without this call, the workers continue to
poll for new tasks in a tight loop, wasting CPU time. The symmetric
call to starpu_resume() should be used to unfreeze the workers.

\fn void starpu_resume(void)
\ingroup API_Initialization_and_Termination
This is the symmetrical call to starpu_pause(), used to resume
the workers polling for new tasks.

\fn int starpu_asynchronous_copy_disabled(void)
\ingroup API_Initialization_and_Termination
Return 1 if asynchronous data transfers between CPU and accelerators
are disabled.

\fn int starpu_asynchronous_cuda_copy_disabled(void)
\ingroup API_Initialization_and_Termination
Return 1 if asynchronous data transfers between CPU and CUDA
accelerators are disabled.

\fn int starpu_asynchronous_opencl_copy_disabled(void)
\ingroup API_Initialization_and_Termination
Return 1 if asynchronous data transfers between CPU and OpenCL
accelerators are disabled.

\fn void starpu_topology_print(FILE *f)
\ingroup API_Initialization_and_Termination
Prints a description of the topology on f.

*/