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SPU_CREATE(2)		   Linux Programmers Manual		SPU_CREATE(2)

       spu_create - create a new spu context


       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);

       The spu_create() system call is used on PowerPC machines that implement
       the Cell Broadband Engine Architecture in order to  access  Synergistic
       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 non-existing directory in the mount point of the SPU
       file system (spufs).  If spu_create() is  successful,  a  directory  is
       created	at  pathname  and  it is populated with the files described in

       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 contexts 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:

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

	      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().

	      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 func
	      tionality 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

	      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_CRE
	      ATE_NOSCHED flag.

	      Create  a  context  with	affinity to another SPU context.  This
	      affinity information is used within  the	SPU  scheduling  algo
	      rithm.   Using  this flag requires that a file descriptor refer
	      ring to the other SPU context be passed in the neighbor_fd argu

	      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 processs umask(2)) speci
       fies the permissions used for creating the new directory in spufs.  See
       stat(2) for a full list of the possible mode values.

       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.

       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  processs
	      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.

	      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  con
	      texts 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.

	      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.

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

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

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

       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/deep
       computing/linuxoncell/ for the recommended libraries.

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

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

       This page is part of release 3.05 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				  2007-12-20			 SPU_CREATE(2)

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