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       spu_create - create a new spu context


       Standard C library (libc, -lc)


       #include <sys/spu.h>          /* Definition of SPU_* constants */
       #include <sys/syscall.h>      /* Definition of SYS_* constants */
       #include <unistd.h>

       int syscall(SYS_spu_create, const char *pathname, unsigned int flags,
                   mode_t mode, int neighbor_fd);

       Note: glibc provides no wrapper for spu_create(), necessitating the use of syscall(2).


       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  nonexistent  directory  in  the  mount  point  of  the  SPU
       filesystem (spufs).  If spu_create() is successful, a directory 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  created  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

       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.

       The  neighbor_fd  is  used  only  when  the SPU_CREATE_AFFINITY_SPU flag is specified; see

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

              Rather  than  using  signals  for  reporting  DMA errors, use the event argument to

              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 contexts, 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 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.

              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 (since Linux 2.6.23)
              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

       SPU_CREATE_AFFINITY_MEM (since Linux 2.6.23)
              Create a context with affinity to system memory.  This affinity information is used
              within the SPU scheduling algorithm.


       On  success,  spu_create() returns a new file descriptor.  On failure, -1 is returned, and
       errno is set to indicate the error.


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

       EEXIST An SPU context already exists at the given pathname.

       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

       ELOOP  Too many symbolic links were found while resolving pathname.

       EMFILE The per-process limit on the number of open file descriptors has been reached.

              pathname is too long.

       ENFILE The system-wide limit on the total number of open files has been reached.

       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.

              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 in Linux 2.6.16.


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


       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 ⟨
       /deepcomputing/linuxoncell/⟩ for the recommended libraries.

       Prior  to  the  addition  of  the  SPU_CREATE_AFFINITY_SPU  flag  in  Linux  2.6.23,   the
       spu_create()  system  call  took  only  three  arguments  (i.e.,  there was no neighbor_fd


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


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