SPU_CREATE(2)						     Linux Programmer's Manual						     SPU_CREATE(2)

NAME

       spu_create - create a new spu context

SYNOPSIS

       #include <sys/types.h>
       #include <sys/spu.h>

       int spu_create(const char *pathname, int flags, mode_t mode);
       int spu_create(const char *pathname, int flags, mode_t mode,
		      int neighbor_fd);

       Note: There is no glibc wrapper for this system call; see NOTES.

DESCRIPTION

       The spu_create() system call is used on PowerPC machines that implement the Cell Broadband Engine Architecture in order to access Synergis-
       tic Processor Units (SPUs).  It creates a new logical context for an SPU in pathname and returns a  file  descriptor  associated  with  it.
       pathname  must refer to a nonexistent directory in the mount point of the SPU file system (spufs).  If spu_create() is successful, a direc-
       tory is created at pathname and it is populated with the files described in spufs(7).

       When a context is created, the returned file descriptor can only be passed to spu_run(2), used as the dirfd argument to the *at	family	of
       system calls (e.g., openat(2)), or closed; other operations are not defined.  A logical SPU context is destroyed (along with all files cre-
       ated within the context's pathname directory) once the last reference to the context has gone; this usually occurs when the file descriptor
       returned by spu_create() is closed.

       The flags argument can be zero or any bitwise OR-ed combination of the following constants:

       SPU_CREATE_EVENTS_ENABLED
	      Rather than using signals for reporting DMA errors, use the event argument to spu_run(2).

       SPU_CREATE_GANG
	      Create  an  SPU gang instead of a context.  (A gang is a group of SPU contexts that are functionally related to each other and which
	      share common scheduling parameters--priority and policy.	In the future, gang scheduling may be implemented causing the group to	be
	      switched in and out as a single unit.)

	      A  new  directory  will be created at the location specified by the pathname argument.  This gang may be used to hold other SPU con-
	      texts, by providing a pathname that is within the gang directory to further calls to spu_create().

       SPU_CREATE_NOSCHED
	      Create a context that is not affected by the SPU scheduler.  Once the context is run, it will not  be  scheduled	out  until  it	is
	      destroyed by the creating process.

	      Because  the  context cannot be removed from the SPU, some functionality is disabled for SPU_CREATE_NOSCHED contexts.  Only a subset
	      of the files will be available in this context directory in spufs.  Additionally, SPU_CREATE_NOSCHED contexts  cannot  dump  a  core
	      file when crashing.

	      Creating SPU_CREATE_NOSCHED contexts requires the CAP_SYS_NICE capability.

       SPU_CREATE_ISOLATE
	      Create  an  isolated  SPU  context.   Isolated contexts are protected from some PPE (PowerPC Processing Element) operations, such as
	      access to the SPU local store and the NPC register.

	      Creating SPU_CREATE_ISOLATE contexts also requires the SPU_CREATE_NOSCHED flag.

       SPU_CREATE_AFFINITY_SPU
	      Create a context with affinity to another SPU context.  This affinity information is  used  within  the  SPU  scheduling	algorithm.
	      Using this flag requires that a file descriptor referring to the other SPU context be passed in the neighbor_fd argument.

       SPU_CREATE_AFFINITY_MEM
	      Create a context with affinity to system memory.	This affinity information is used within the SPU scheduling algorithm.

       The  mode  argument  (minus any bits set in the process's umask(2)) specifies the permissions used for creating the new directory in spufs.
       See stat(2) for a full list of the possible mode values.

RETURN VALUE

       On success, spu_create() returns a new file descriptor.	On error, -1 is returned, and errno is set to one of the error codes listed below.

ERRORS

       EACCES The current user does not have write access to the spufs(7) mount point.

       EEXIST An SPU context already exists at the given path name.

       EFAULT pathname is not a valid string pointer in the calling process's address space.

       EINVAL pathname is not a directory in the spufs(7) mount point, or invalid flags have been provided.

       ELOOP  Too many symbolic links were found while resolving pathname.

       EMFILE The process has reached its maximum open files limit.

       ENAMETOOLONG
	      pathname is too long.

       ENFILE The system has reached the global open files limit.

       ENODEV An isolated context was requested, but the hardware does not support SPU isolation.

       ENOENT Part of pathname could not be resolved.

       ENOMEM The kernel could not allocate all resources required.

       ENOSPC There are not enough SPU resources available to create a new context or the user-specific limit for the number of SPU  contexts  has
	      been reached.

       ENOSYS The  functionality  is  not provided by the current system, because either the hardware does not provide SPUs or the spufs module is
	      not loaded.

       ENOTDIR
	      A part of pathname is not a directory.

       EPERM  The SPU_CREATE_NOSCHED flag has been given, but the user does not have the CAP_SYS_NICE capability.

FILES

       pathname must point to a location beneath the mount point of spufs.  By convention, it gets mounted in /spu.

VERSIONS

       The spu_create() system call was added to Linux in kernel 2.6.16.

CONFORMING TO

       This call is Linux-specific and only implemented on the PowerPC architecture.  Programs using this system call are not portable.

NOTES

       Glibc does not provide a wrapper for this system call; call it using syscall(2).  Note however, that spu_create() is meant to be used  from
       libraries  that	implement  a  more  abstract interface to SPUs, not to be used from regular applications.  See <http://www.bsc.es/projects
       /deepcomputing/linuxoncell/> for the recommended libraries.

EXAMPLE

       See spu_run(2) for an example of the use of spu_create()

SEE ALSO

       close(2), spu_run(2), capabilities(7), spufs(7)

COLOPHON

       This page is part of release 3.44 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

Linux								    2012-08-05							     SPU_CREATE(2)